<PAGE>

                                                                   EXHIBIT 10.26

Promissory Note                             Master Security Agreement No.6081111
                                                                  Schedule No. 1

                                 PROMISSORY NOTE
                    To Master Security Agreement No. 6081111
                                 MARCH 31, 2006

FOR VALUE RECEIVED, athenahealth, Inc., a Delaware corporation, located at the
address stated below ("Maker") promises to pay to the order of Oxford Finance
Corporation or any subsequent holder hereof (each, a "Payee") at its office
located at 133 N. Fairfax STREET, ALEXANDRIA, VA 22314 or at such other place as
Payee or the holder hereof may designate, the principal sum of ONE MILLION EIGHT
HUNDRED Seventy Thousand Four HUNDRED TWENTY-ONE AND 36/100 DOLLARS
($1,870,421.36), with interest on the unpaid principal balance, from the date
hereof through and including the dates of payment, at a fixed interest rate of
Ten and Sixty-Nine One Hundredths of One Percent (10.69%) per annum, in thirty
six (36) consecutive monthly installments of principal and interest (each, a
"Periodic Installment") as follows:

<TABLE>
<CAPTION>
  Periodic
Installment        Amount
-----------   ---------------
<S>           <C>
I- 36         $60,422.71 each
</TABLE>

and a final installment which shall be in the amount of the total outstanding
principal and interest, if any. The first Periodic Installment shall be due and
payable on or about March 31, 2006, and each of the following Periodic
Installments and the final installment shall be due and payable on the first day
of each succeeding month (each, a "Payment Date") beginning May 1, 2006. Such
installments have been calculated on the basis of a 360-day year of twelve
30-day months. Each payment may, at the option of the Payee, be calculated and
applied on an assumption that such payment would be made on its due date. Maker
agrees to pay any initial partial month interest payment from the date of this
Note to the first day of the following month ("Interim Interest").

The acceptance by Payee of any payment which is less than payment in full of all
amounts due and owing at such time shall not constitute a waiver of Payee's
right to receive payment in full at such time or at any prior or subsequent
time.

The Maker hereby expressly authorizes the Payee to insert the date value is
actually given in the blank space on the face hereof and on all related
documents pertaining hereto.

This Note may be secured by a security agreement, chattel mortgage, pledge
agreement or like instrument (each of which is hereinafter called a "SECURITY
AGREEMENT" AND ANY Security Agreement, this Note and any other document
evidencing or securing this loan is hereinafter called a "Debt Document").

Time is of the essence hereof, If any installment or any other sum due under
this Note or any Security Agreement is not received within five (5) days of when
due, the Maker agrees to pay, in addition to the amount of each such installment
or other sum, a late payment charge of five percent (5%) of the amount of said
installment or other sum, but not exceeding any lawful maximum. If (i) Maker
fails to make payment of any amount due hereunder; or (ii) Maker is in default
under, or fails to perform under any term or condition contained in any Security
Agreement, then the entire principal sum remaining unpaid, together with all
accrued interest thereon and any other sum payable under this Note or any
Security Agreement, at the election of Payee, shall immediately become due and
payable, with interest thereon at the lesser of eighteen percent (18%) per annum
or the highest rate not prohibited by applicable law from the date of such
accelerated maturity until paid (both before and after any judgment).

For a period of ninety (90) days immediately following the date of closing of
either (i) Maker's initial public offering of its Common Stock or (ii) the
merger or consolidation of Maker with or the sale of a majority of Maker's
outstanding voting capital stock to an entity with a post-closing market
capitalization of at least $400 million, Maker shall be entitled to prepay in
full, but not in part, its entire Indebtedness hereunder by payment of the
entire Indebtedness plus an additional sum as a premium equal to the following
percentages of the remaining principal balance for the indicated period:

     From the date of this Note until the first anniversary of the date of this
     Note: three percent (3%)


                                   Page 1 of 4

<PAGE>

Promissory Note                             Master Security Agreement No.6081111
                                                                  Schedule No. 1

     From the first annual anniversary date of this Note until the second annual
     anniversary date of this Note: two percent (2%)

     From the second annual anniversary date of this Note until the third annual
     anniversary date of this Note: one percent (I%)

At all other times and notwithstanding anything to the contrary contained herein
or in the Security Agreement, Maker may prepay in full, but not in part, its
entire Indebtedness hereunder by payment of the entire Indebtedness plus an
additional sum as a premium equal to the following percentages of the remaining
principal balance for the indicated period:

     From the date of this Note until the first anniversary of the date of this
     Note: six percent (6%)

     From the first annual anniversary date of this Note until the second annual
     anniversary date of this Note: four percent (4%)

     From the second annual anniversary date of this Note until the third annual
     anniversary date of this Note: two percent (2%)

The Maker and all sureties, endorsers, guarantors, or any others (each such
person, other than the Maker, an "Obligor") who may at any time become liable
for the payment hereof jointly and severally consent hereby to any and all
extensions of time, renewals, waivers or modifications of, and all substitutions
or releases of, security or of any party primarily or secondarily liable on this
Note or any Security Agreement or any term and provision of either, which may be
made, granted or consented to by Payee, and agree that suit may be brought and
maintained against any one or more of them, at the election of Payee without
joinder of any other as a party thereto, and that Payee shall not be required
first to foreclose, proceed against, or exhaust any security hereof in order to
enforce payment of this Note. The Maker and each Obligor hereby waives
presentment, demand for payment, notice of nonpayment, protest, notice of
protest, notice of dishonor, and all other notices in connection herewith, as
well as filing of suit (it' permitted by law) and diligence in collecting this
Note or enforcing any of the security hereof, and agrees to pay (if and to the
extent permitted by law) all expenses incurred in collection, including Payee's
actual attorneys' fees.

Maker and Payee intend to strictly comply with all applicable federal and
Virginia laws, including applicable usury laws (or the usury laws of any
jurisdiction whose usury laws are deemed to apply to the Note or any other Debt
Document despite the intention and desire of the parties to apply the usury laws
of the Commonwealth of Virginia). Accordingly, the provisions of this paragraph
shall govern and control over every other provision of this Note or any other
Debt Document which conflicts or is inconsistent with this Section, even if such
provision declares that it controls. As used in this paragraph, the term
"interest" includes the aggregate of all charges, fees, benefits or other
compensation which constitute interest under applicable law, provided that, to
the maximum extent permitted by applicable law, (a) any non-principal payment
shall be characterized as an expense or as compensation for something other than
the use, forbearance or detention of money and not as interest, and (b) all
interest at any time contracted for, reserved, charged or received shall be
amortized, prorated, allocated and spread, in equal parts during the full term
of the obligations. In no event shall Maker or any other person be obligated to
pay, or Payee have any right or privilege to reserve, receive or retain, (a) any
interest in excess of the maximum amount of non-usurious interest permitted
under the laws of the Commonwealth of Virginia or the applicable laws (if any)
of the United States or of any other state, or (b) total interest in excess of
the amount which Payee could lawfully have contracted for, reserved, received,
retained or charged had the interest been calculated for the full term of the
obligations. On each day, if any, that the interest rate (the "Stated Rate")
called for under this Note or any other Debt Document exceeds the maximum
non-usurious rate, the rate at which interest shall accrue shall automatically
be fixed by operation of this sentence at the maximum non-usurious rate for that
day. Thereafter, interest shall accrue at the Stated Rate unless and until the
Stated Rate again exceeds the maximum non-usurious rate, in which case, the
provisions of the immediately preceding sentence shall again automatically
operate to limit the interest accrual rate to the maximum non-usurious rate. The
daily interest rates to be used in calculating interest at the maximum
non-usurious rate shall be determined by dividing the applicable maximum
non-usurious rate by the number of days in the calendar year for which such
calculation is being made. None of the terms and provisions contained in this
Note or in any other Debt Document which directly or indirectly relate to
interest shall ever be construed without


                                   Page 2 of 4

<PAGE>

Promissory Note                             Master Security Agreement No.6081111
                                                                  Schedule No. 1

reference to this paragraph, or be construed to create a contract to pay for the
use, forbearance or detention of money at an interest rate in excess of the
maximum non-usurious rate. If the term of any obligation is shortened by reason
of acceleration of maturity as a result of any Default or by any other cause, or
by reason of any required or permitted prepayment, and if for that (or any
other) reason Payee at any time, including but not limited to, the stated
maturity, is owed or receives (and/or has received) interest in excess of
interest calculated at the maximum non-usurious rate, then and in any such event
all of any such excess interest shall be canceled automatically as of the date
of such acceleration, prepayment or other event which produces the excess, and,
if such excess interest has been paid to Payee, it shall be credited pro tanto
against the then-outstanding principal balance of Maker's obligations to Payee,
effective as of the date or dates when the event occurs which causes it to be
excess interest, until such excess is exhausted or ail of such principal has
been fully paid and satisfied, whichever occurs first, and any remaining balance
of such excess shall be promptly refunded to its payor.

THE MAKER HEREBY UNCONDITIONALLY WAIVES ITS RIGHTS TO A JURY TRIAL OF ANY CLAIM
OR CAUSE OF ACTION BASED UPON OR ARISING OUT OF, DIRECTLY OR INDIRECTLY, THIS
NOTE, ANY OF THE RELATED DOCUMENTS, ANY DEALINGS BETWEEN MAKER AND PAYEE
RELATING TO THE SUBJECT MATTER OF THIS TRANSACTION OR ANY RELATED TRANSACTIONS,
AND/OR THE RELATIONSHIP THAT IS BEING ESTABLISHED BETWEEN MAKER AND PAYEE. THE
SCOPE OF THIS WAIVER IS INTENDED TO BE ALL ENCOMPASSING OF ANY AND ALL DISPUTES
THAT MAY BE FILED IN ANY COURT (INCLUDING, WITHOUT LIMITATION, CONTRACT CLAIMS,
TORT CLAIMS, BREACH OF DUTY CLAIMS, AND ALL OTHER COMMON LAW AND STATUTORY
CLAIMS.) THIS WAIVER IS IRREVOCABLE, MEANING THAT IT MAY NOT BE MODIFIED EITHER
ORALLY OR IN WRITING, AND THE WAIVER SHALL APPLY TO ANY SUBSEQUENT AMENDMENTS,
RENEWALS, SUPPLEMENTS OR MODIFICATIONS TO THIS NOTE, ANY RELATED DOCUMENTS, OR
TO ANY OTHER DOCUMENTS OR AGREEMENTS RELATING TO THIS TRANSACTION OR ANY RELATED
TRANSACTION. IN THE EVENT OF LITIGATION, THIS NOTE MAY BE FILED AS A WRITTEN
CONSENT TO A TRIAL BY THE COURT.

This Note and any Security Agreement constitute the entire agreement of the
Maker and Payee with respect to the subject matter hereof and supersedes all
prior understandings, agreements and representations, express or implied.

No variation or modification of this Note, or any waiver of any of its
provisions or conditions, shall be valid unless in writing and signed by an
authorized representative of Maker and Payee. Any such waiver, consent,
modification or change shall be effective only in the specific instance and for
the specific purpose given.

Any provision in this Note or any Security Agreement which is in conflict with
any statute, law or applicable rule shall be deemed omitted, modified or altered
to conform thereto.

Upon receipt of an affidavit of an officer of Payee as to the loss, theft,
destruction or mutilation of this Note or any Debt Document which is not of
public record, and, in the case of any such loss, theft, destruction or
mutilation, upon surrender and cancellation of such Note or other Debt Document,
Maker will issue, in lieu thereof, a replacement Note or other Debt Document in
the same principal amount thereof and otherwise of like tenor.

It is understood and agreed that this Note and all of the Debt Documents were
negotiated and have been or will be delivered to Payee in the Commonwealth of
Virginia, which State the parties agree has a substantial relationship to the
parties and to the underlying transactions embodied by this Note and the Debt
Documents. Maker agrees to furnish to Payee at Payee's office in Alexandria, VA,
all further instruments, certifications and documents to be furnished hereunder.
The parties also agree that if collateral is pledged to secure the debt
evidenced by this Note, that the state or states in which such collateral is
located each have a substantial relationship to the parties and to the
underlying transaction embodied by this Note and the Debt Documents.

MAKER AGREES THAT THE PAYEE OF THIS NOTE SHALL HAVE THE OPTION BY WHICH STATE
LAWS THIS NOTE SHALL BE GOVERNED AND CONSTRUED: (A) THE LAWS OF THE COMMONWEALTH
OF VIRGINIA; OR (B) IF COLLATERAL HAS BEEN PLEDGED TO SECURE THE DEBT EVIDENCED
BY THIS NOTE, THEN BY THE LAWS OF THE STATE OR STATES WHERE THE


                                   Page 3 of 4

<PAGE>

Promissory Note                             Master Security Agreement No.6081111
                                                                  Schedule No. 1

COLLATERAL IS LOCATED, AT PAYEE'S OPTION. THIS CHOICE OF STATE LAWS IS EXCLUSIVE
TO THE PAYEE OF THIS NOTE. MAKER SHALL NOT HAVE ANY OPTION TO CHOOSE THE LAWS BY
WHICH THIS NOTE SHALL BE GOVERNED. MAKER AND GUARANTORS HEREBY CONSENT TO THE
EXERCISE OF JURISDICTION OVER IT BY ANY FEDERAL COURT SITTING IN VIRGINIA OR ANY
VIRGINIA COURT SELECTED BY PAYEE, FOR THE PURPOSES OF ANY AND ALL LEGAL
PROCEEDINGS ARISING OUT OF OR RELATING TO THE NOTE, THE LOAN AGREEMENT AND ALL
OTHER DOCUMENTS. MAKER AND GUARANTORS IRREVOCABLY WAIVE, TO THE FULLEST EXTENT
PERMITTED BY LAW, ANY OBJECTION WHICH IT MAY NOW OR HEREAFTER HAVE TO THE LAYING
OF VENUE OF ANY SUCH PROCEEDING BROUGHT IN ANY SUCH COURT, ANY CLAIM BASED ON
THE CONSOLIDATION OF PROCEEDINGS IN SUCH COURTS IN WHICH PROPER VENUE MAY LIE IN
DIVERGENT JURISDICTIONS. AND ANY CLAIM THAT ANY SUCH PROCEEDING BROUGHT IN ANY
SUCH COURT HAS BEEN BROUGHT IN AN INCONVENIENT FORUM. MAKER AND GUARANTORS
HEREBY IRREVOCABLY WAIVE, TO THE FULLEST EXTENT PERMITTED BY LAW, ANY AND ALL
RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO
THIS NOTE, THE OTHER DOCUMENTS OR THE TRANSACTIONS CONTEMPLATED THEREBY.

                                        athenahealth, Inc.


                                        By: /s/ Jonathan Bush
-------------------------------------       ------------------------------------
(Witness)                               Name: Jonathan Bush
                                        Title: CEO
-------------------------------------
(Print name)

-------------------------------------
(Address)

                                        Federal Tax ID #. 04-3387530

                                        Address: 311 Arsenal Street
                                                 Watertown, MA 02472


                                   Page 4 of 4
<PAGE>


                                 PROMISSORY NOTE
                    To Master Security Agreement No. 6081111
                                    June 2006

FOR VALUE RECEIVED, athenahealth, Inc., a Delaware corporation, located at the
address stated below ("Maker") promises to pay to the order of Oxford Finance
Corporation or any subsequent holder hereof (each, a "Payee") at its office
located at 133 N. Fairfax Street, Alexandria, VA 22314 Of at such other place as
Payee or the holder hereof may designate, the principal sum of One Million One
Hundred Ninety-Six Thousand, One Hundred Eighty-Four and Sixty-Eight
One-Hundredths Dollars ($1,196,184.68), with interest on the unpaid principal
balance, from the date hereof through and including the dates of payment, at a
fixed interest rate of Eleven and Four One-Hundredths Percent (11.04%) per
annum, in thirty six (36) consecutive monthly installments of principal and
interest (each, a "Periodic Installment") as follows:

<TABLE>
<CAPTION>
  Periodic
Installment        Amount
-----------   ---------------
<S>           <C>
1 - 36        $38,827.01 each
</TABLE>

and a final installment which shall be in the amount of the total outstanding
principal and interest, if any. The first Periodic Installment shall be due and
payable on or about June 21,2006, and each of the following Periodic
Installments and the final installment shall be due and payable on the first day
of each succeeding month (each, a "Payment Date") beginning August 1, 2006. Such
installments have been calculated on the basis of a 360-day year of twelve
30-day months. Each payment may, at the option of the Payee, be calculated and
applied on an assumption that such payment would be made on its due date. Maker
agrees to pay any initial partial month interest payment from the date of this
Note to the first day of the following month ("Interim Interest").

The acceptance by Payee of any payment which is less than payment in full of all
amounts due and owing at such time shall not constitute a waiver of Payee's
right to receive payment in full at such time or at any prior or subsequent
time.

The Maker hereby expressly authorizes the Payee to insert the date value is
actually given in the blank space on the face hereof and on all related
documents pertaining hereto.

This Note may be secured by a security agreement, chattel mortgage, pledge
agreement or like instrument (each of which is hereinafter called a "Security
Agreement" and any Security Agreement, this Note and any other document
evidencing or securing this loan is hereinafter called a "Debt Document").

Time is of the essence hereof. If any installment or any other sum due under
this Note or any Security Agreement is not received within five (5) days of when
due, the Maker agrees to pay, in addition to the amount of each such installment
or other sum, a late payment charge of five percent (5%) of the amount of said
installment or other sum, but not exceeding any lawful maximum. If (i) Maker
fails to make payment of any amount due hereunder; or (ii) Maker is in default
under, or fails to perform under any term or condition contained in any Security
Agreement, then the entire principal sum remaining unpaid, together with all
accrued interest

<PAGE>

thereon and any other sum payable under this Note or any Security Agreement, at
the election of Payee, shall immediately become due and payable, with interest
thereon at the lesser of eighteen percent (18%) per annum or the highest rate
not prohibited by applicable law from the date of such accelerated maturity
until paid (both before and after any judgment).

For a period of ninety (90) days immediately following the date of closing of
either (i) Maker's initial public offering of its Common Stock or (ii) the
merger or consolidation of Maker with or the sale of a majority of Maker's
outstanding voting capital stock to an entity with a post-closing market
capitalization of at least $400 million, Maker shall be entitled to prepay in
full, but not in part, its entire Indebtedness hereunder by payment of the
entire Indebtedness plus an additional sum as a premium equal to the following
percentages of the remaining principal balance for the indicated period:

     From the date of this Note until the first anniversary of the date of this
     Note: three percent (3%)

     From the first annual anniversary date of this Note until the second annual
     anniversary date of this Note: two percent (2%)

     From the second annual anniversary date of this Note until the third annual
     anniversary date of this Note: one percent (1%)

At all other times and notwithstanding anything to the contrary contained herein
or in the Security Agreement, Maker may prepay in full, but not in part, its
entire Indebtedness hereunder by payment of the entire Indebtedness plus an
additional sum as a premium equal to the following percentages of the remaining
principal balance for the indicated period:

     From the date of this Note until the first anniversary of the date of this
     Note: six percent (6%)

     From the first annual anniversary date of this Note until the second annual
     anniversary date of this Note: four percent (4%)

     From the second annual anniversary date of this Note until the third annual
     anniversary date of this Note: two percent (2%)

The Maker and all sureties, endorsers, guarantors, or any others (each such
person, other than the Maker, an "Obligor") who may at any time become liable
for the payment hereof jointly and severally consent hereby to any and all
extensions of time, renewals, waivers or modifications of, and all substitutions
or releases of, security or of any party primarily or secondarily liable on this
Note or any Security Agreement or any term and provision of either, which may be
made, granted or consented to by Payee, and agree that suit may be brought and
maintained against any one or more of them, at the election of Payee without
joinder of any other as a party thereto, and that Payee shall not be required
fast to foreclose, proceed against, or exhaust any security hereof in order to
enforce payment of this Note. The Maker and each Obligor hereby waives
presentment, demand for payment, notice of nonpayment, protest, notice of
protest, notice of dishonor, and all other notices in connection herewith, as
well as filing of suit (if permitted by law) and diligence in collecting this
Note or enforcing any of the security hereof, and agrees to

<PAGE>

pay (if and to the extent permitted by law) all expenses incurred in collection,
including Payee's actual attorneys' fees.

Maker and Payee intend to strictly comply with all applicable federal and
Virginia laws, including applicable usury laws (or the usury laws of any
jurisdiction whose usury laws are deemed to apply to the Note or any other Debt
Document despite the intention and desire of the parties to apply the usury laws
of the Commonwealth of Virginia). Accordingly, the provisions of this paragraph
shall govern and control over every other provision of this Note or any other
Debt Document which conflicts or is inconsistent with this Section, even if such
provision declares that it controls. As used in this paragraph, the term
"interest" includes the aggregate of all charges, fees, benefits or other
compensation which constitute interest under applicable law, provided that, to
the maximum extent permitted by applicable law, (a) any non-principal payment
shall be characterized as an expense or as compensation for something other than
the use, forbearance or detention of money and not as interest, and (b) all
interest at any time contracted for, reserved, charged or received shall be
amortized, prorated, allocated and spread, in equal parts during the full term
of the obligations. In no event shall Maker or any other person be obligated to
pay, or Payee have any right or privilege to reserve, receive or retain, (a) any
interest in excess of the maximum amount of non-usurious interest permitted
under the laws of the Commonwealth of Virginia or the applicable laws (if any)
of the United States or of any other state, or (b) total interest in excess of
the amount which Payee could lawfully have contracted for, reserved, received,
retained or charged had the interest been calculated for the full term of the
obligations. On each day, if any, that the interest rate (the "Stated Rate")
called for under this Note or any other Debt Document exceeds the maximum
non-usurious rate, the rate at which interest shall accrue shall automatically
be fixed by operation of this sentence at the maximum non-usurious rate for that
day. Thereafter, interest shall accrue at the Stated Rate unless and until the
Stated Rate again exceeds the maximum non-usurious rate, in which case, the
provisions of the immediately preceding sentence shall again automatically
operate to limit the interest accrual rate to the maximum non-usurious rate. The
daily interest rates to be used in calculating interest at the maximum
non-usurious rate shall be determined by dividing the applicable maximum
non-usurious rate by the number of days in the calendar year for which such
calculation is being made. None of the terms and provisions contained in this
Note or in any other Debt Document which directly or indirectly relate to
interest shall ever be construed without reference to this paragraph, or be
construed to create a contract to pay for the use, forbearance or detention of
money at an interest rate in excess of the maximum non-usurious rate. If the
term of any obligation is shortened by reason of acceleration of maturity as a
result of any Default or by any other cause, or by reason of any required or
permitted prepayment, and if for that (or any other) reason Payee at any time,
including but not limited to, the stated maturity, is owed or receives (and/or
has received) interest in excess of interest calculated at the maximum
non-usurious rate, then and in any such event all of any such excess interest
shall be canceled automatically as of the date of such acceleration, prepayment
or other event which produces the excess, and, if such excess interest has been
paid to Payee, it shall be credited pro tanto against the then-outstanding
principal balance of Makers obligations to Payee, effective as of the date or
dates when the event occurs which causes it to be excess interest, until such
excess is exhausted or all of such principal has been fully paid and satisfied,
whichever occurs first, and any remaining balance of such excess shall be
promptly refunded to its payor.

<PAGE>

THE MAKER HEREBY UNCONDITIONALLY WAIVES ITS RIGHTS TO A JURY TRIAL OF ANY CLAIM
OR CAUSE OF ACTION BASED UPON OR ARISING OUT OF, DIRECTLY OR INDIRECTLY, THIS
NOTE, ANY OF THE RELATED DOCUMENTS, ANY DEALINGS BETWEEN MAKER AND PAYEE
RELATING TO THE SUBJECT MATTER OF THIS TRANSACTION OR ANY RELATED TRANSACTIONS,
AND/OR THE RELATIONSHIP THAT IS BEING ESTABLISHED BETWEEN MAKER AND PAYEE. THE
SCOPE OF THIS WAIVER IS INTENDED TO BE ALL ENCOMPASSING OF ANY AND ALL DISPUTES
THAT MAY BE FILED IN ANY COURT (INCLUDING, WITHOUT LIMITATION, CONTRACT CLAIMS,
TORT CLAIMS, BREACH OF DUTY CLAIMS, AND ALL OTHER COMMON LAW AND STATUTORY
CLAIMS.) THIS WAIVER IS IRREVOCABLE, MEANING THAT IT MAY NOT BE MODIFIED EITHER
ORALLY OR IN WRITING, AND THE WAIVER SHALL APPLY TO ANY SUBSEQUENT AMENDMENTS,
RENEWALS, SUPPLEMENTS OR MODIFICATIONS TO THIS NOTE, ANY RELATED DOCUMENTS, OR
TO ANY OTHER DOCUMENTS OR AGREEMENTS RELATING TO THIS TRANSACTION OR ANY RELATED
TRANSACTION. IN THE EVENT OF LITIGATION, THIS NOTE MAY BE FILED AS A WRITTEN
CONSENT TO A TRIAL BY THE COURT.

This Note and any Security Agreement constitute the entire agreement of the
Maker and Payee with respect to the subject matter hereof and supersedes all
prior understandings, agreements and representations, express or implied.

No variation or modification of this Note, or any waiver of any of its
provisions or conditions, shall be valid unless in writing and signed by an
authorized representative of Maker and Payee. Any such waiver, consent,
modification or change shall be effective only in the specific instance and for
the specific purpose given.

Any provision in this Note or any Security Agreement which is in conflict with
any statute, law or applicable rule shall be deemed omitted, modified or altered
to conform thereto.

Upon receipt of an affidavit of an officer of Payee as to the loss, theft,
destruction or mutilation of this Note or any Debt Document which is not of
public record, and, in the case of any such loss, theft, destruction or
mutilation, upon surrender and cancellation of such Note or other Debt Document,
Maker will issue, in lieu thereof, a replacement Note or other Debt Document in
the same principal amount thereof and otherwise of like tenor.

It is understood and agreed that this Note and all of the Debt Documents were
negotiated and have been or will be delivered to Payee in the Commonwealth of
Virginia, which State the parties agree has a substantial relationship to the
parties and to the underlying transactions embodied by this Note and the Debt
Documents. Maker agrees to furnish to Payee at Payee's office in Alexandria, VA,
all further instruments, certifications and documents to be furnished hereunder.
The parties also agree that if collateral is pledged to secure the debt
evidenced by this Note, that the state or states in which such collateral is
located each have a substantial relationship to the parties and to the
underlying transaction embodied by this Note and the Debt Documents.

<PAGE>

MAKER AGREES THAT THE PAYEE OF THIS NOTE SHALL HAVE THE OPTION BY WHICH STATE
LAWS THIS NOTE SHALL BE GOVERNED AND CONSTRUED: (A) THE LAWS OF THE COMMONWEALTH
OF VIRGINIA; OR (B) IF COLLATERAL HAS BEEN PLEDGED TO SECURE THE DEBT EVIDENCED
BY THIS NOTE, THEN BY THE LAWS OF THE STATE OR STATES WHERE THE COLLATERAL IS
LOCATED, AT PAYEE'S OPTION. THIS CHOICE OF STATE LAWS IS EXCLUSIVE TO THE PAYEE
OF THIS NOTE. MAKER SHALL NOT HAVE ANY OPTION TO CHOOSE THE LAWS BY WHICH THIS
NOTE SHALL BE GOVERNED. MAKER AND GUARANTORS HEREBY CONSENT TO THE EXERCISE OF
JURISDICTION OVER IT BY ANY FEDERAL COURT SITTING IN VIRGINIA OR ANY VIRGINIA
COURT SELECTED BY PAYEE, FOR THE PURPOSES OF ANY AND ALL LEGAL PROCEEDINGS
ARISING OUT OF OR RELATING TO THE NOTE, THE LOAN AGREEMENT AND ALL OTHER
DOCUMENTS. MAKER AND GUARANTORS IRREVOCABLY WAIVE, TO THE FULLEST EXTENT
PERMITTED BY LAW, ANY OBJECTION WHICH IT MAY NOW OR HEREAFTER HAVE TO THE LAYING
OF VENUE OF ANY SUCH PROCEEDING BROUGHT IN ANY SUCH COURT, ANY CLAIM BASED ON
THE CONSOLIDATION OF PROCEEDINGS IN SUCH COURTS IN WHICH PROPER VENUE MAY LIE IN
DIVERGENT JURISDICTIONS, AND ANY CLAIM THAT ANY SUCH PROCEEDING BROUGHT IN ANY
SUCH COURT HAS BEEN BROUGHT IN AN INCONVENIENT FORUM. MAKER AND GUARANTORS
HEREBY IRREVOCABLY WAIVE, TO THE FULLEST EXTENT PERMITTED BY LAW, ANY AND ALL
RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO
THIS NOTE, THE OTHER DOCUMENTS OR THE TRANSACTIONS CONTEMPLATED THEREBY.

                                        Athenahealth, Inc.


/s/ Scott Andrews                       By: /s/ Carl Byers
-------------------------------------       ------------------------------------
(Witness)                               Name: Carl Byers
                                        Title: CFO
Scott Andrews
(Print name)

311 Arsenal St Watertown, MA 02472
(Address)

                                        Federal Tax ID#: 04-3387530

                                        Address: 311 Arsenal Street
                                                 Watertown, MA 02472
<PAGE>


Promissory Note                             Master Security Agreement No.6081111
                                                                  Schedule No.03

                                 PROMISSORY NOTE
                  TO MASTER SECURITY AGREEMENT NO. 6081111
                               SEPTEMBER 27, 2006

FOR VALUE RECEIVED, athenahealth, Inc., a Delaware corporation, located at the
address stated below ("MAKER") promises to pay to the order of OXFORD FINANCE
CORPORATION or any subsequent holder hereof (each, a "PAYEE") at its office
located at 133 N. FAIRFAX STREET, ALEXANDRIA, VA 22314 or at such other place as
Payee or the holder hereof may designate, the principal sum of FIVE HUNDRED
TWENTY-NINE THOUSAND, ONE HUNDRED SEVENTY-EIGHT AND FORTY-EIGHT ONE-HUNDREDTHS
DOLLARS ($529,178.48), with interest on the unpaid principal balance, from the
date hereof through and including the dates of payment, at a fixed interest rate
of Ten and Sixty-Nine One-Hundredths Percent (10.69%) per annum, in thirty six
(36) consecutive monthly installments of principal and interest (each, a
"PERIODIC INSTALLMENT") as follows:

<TABLE>
<CAPTION>
Periodic
Installment        Amount
-----------   ---------------
<S>           <C>
1-36          $17.094.76 each
</TABLE>

and a final installment which shall be in the amount of the total outstanding
principal and interest, if any. The first Periodic Installment shall be due and
payable on or about September 28, 2006, and each of the following Periodic
Installments and the final installment shall be due and payable on the first day
of each succeeding month (each, a "PAYMENT DATE") beginning November 1, 2006.
Such installments have been calculated on the basis of a 360-day year of twelve
30-day months. Each payment may, at the option of the Payee, be calculated and
applied on an assumption that such payment would be made on its due date. Maker
agrees to pay any initial partial month interest payment from the date of this
Note to the first day of the following month ("Interim Interest").

The acceptance by Payee of any payment which is less than payment in full of all
amounts due and owing at such time shall not constitute a waiver of Payee's
right to receive payment in full at such time or at any prior or subsequent
time.

The Maker hereby expressly authorizes the Payee to insert the date value is
actually given in the blank space on the face hereof and on all related
documents pertaining hereto.

This Note may be secured by a security agreement, chattel mortgage, pledge
agreement or like instrument (each of which is hereinafter called a "SECURITY
AGREEMENT" AND ANY SECURITY AGREEMENT, THIS NOTE AND ANY OTHER DOCUMENT
EVIDENCING OR SECURING THIS LOAN IS HEREINAFTER CALLED A "DEBT DOCUMENT").

Time is of the essence hereof. If any installment or any other sum due under
this Note or any Security Agreement is not received within five (5) days of when
due, the Maker agrees to pay, in addition to the amount of each such installment
or other sum, a late payment charge of five percent (5%) of the amount of said
installment or other sum, but not exceeding any lawful maximum. If (i) Maker
fails to make payment of any amount due hereunder; or (ii) Maker is in default
under, or fails to perform under any term or condition contained in any Security
Agreement, then the entire principal sum remaining unpaid, together with all
accrued interest thereon and any other sum payable under this Note or any
Security Agreement, at the election of Payee, shall immediately become due and
payable, with interest thereon at the lesser of eighteen percent (18%) per annum
or the highest rate not prohibited by applicable law from the date of such
accelerated maturity until paid (both before and after any judgment).

For a period of ninety (90) days immediately following the date of closing of
either (i) Maker's initial public offering of its Common Stock or (ii) the
merger or consolidation of Maker with or the sale of a majority of Maker's
outstanding voting capital stock to an entity with a post-closing market
capitalization of at least $400 million, Maker shall be entitled to prepay in
full, but not in part, its entire Indebtedness hereunder by payment of the
entire Indebtedness plus an additional sum as a premium equal to the following
percentages of the remaining principal balance for the indicated period:


                                   Page 1 of 4

<PAGE>

Promissory Note                             Master Security Agreement No.6081111
                                                                  Schedule No.03

     From the date of this Note until the first anniversary of the date of this
     Note: three percent(3%)

     From the first annual anniversary date of this Note until the second annual
     anniversary date of this Note: two percent (2%)

     From the second annual anniversary date of this Note until the third annual
     anniversary date of this Note: one percent (1%)

At all other times and notwithstanding anything to the contrary contained herein
or in the Security Agreement, Maker may prepay in full, but not in part, its
entire Indebtedness hereunder by payment of the entire Indebtedness plus an
additional sum as a premium equal to the following percentages of the remaining
principal balance for the indicated period:

     From the date of this Note until the first anniversary of the date of this
     Note: six percent (6%)

     From the first annual anniversary date of this Note until the second annual
     anniversary date of this Note: four percent (4%)

     From the second annual anniversary date of this Note until the third annual
     anniversary date of this Note: two percent (2%)

The Maker and all sureties, endorsers, guarantors, or any others (each such
person, other than the Maker, an "Obligor") who may at any time become liable
for the payment hereof jointly and severally consent hereby to any and all
extensions of time, renewals, waivers or modifications of, and all substitutions
or releases of, security or of any party primarily or secondarily liable on this
Note or any Security Agreement or any term and provision of either, which may be
made, granted or consented to by Payee, and agree that suit may be brought and
maintained against any one or more of them, at the election of Payee without
joinder of any other as a party thereto, and that Payee shall not be required
first to foreclose, proceed against, or exhaust any security hereof in order to
enforce payment of this Note. The Maker and each Obligor hereby waives
presentment, demand for payment, notice of nonpayment, protest, notice of
protest, notice of dishonor, and all other notices in connection herewith, as
well as filing of suit (if permitted by law) and diligence in collecting this
Note or enforcing any of the security hereof, and agrees to pay (if and to the
extent permitted by law) all expenses incurred in collection, including Payee's
actual attorneys' fees.

Maker and Payee intend to strictly comply with all applicable federal and
Virginia laws, including applicable usury laws (or the usury laws of any
jurisdiction whose usury laws are deemed to apply to the Note or any other Debt
Document despite the intention and desire of the parties to apply the usury laws
of the Commonwealth of Virginia). Accordingly, the provisions of this paragraph
shall govern and control over every other provision of this Note or any other
Debt Document which conflicts or is inconsistent with this Section, even if such
provision declares that it controls. As used in this paragraph, the term
"INTEREST" includes the aggregate of all charges, fees, benefits or other
compensation which constitute interest under applicable law, provided that, to
the maximum extent permitted by applicable law, (a) any non-principal payment
shall be characterized as an expense or as compensation for something other than
the use, forbearance or detention of money and not as interest, and (b) all
interest at any time contracted for, reserved, charged or received shall be
amortized, prorated, allocated and spread, in equal parts during the full term
of the obligations. In no event shall Maker or any other person be obligated to
pay, or Payee have any right or privilege to reserve, receive or retain, (a) any
interest in excess of the maximum amount of non-usurious interest permitted
under the laws of the Commonwealth of Virginia or the applicable laws (if any)
of the United States or of any other state, or (b) total interest in excess of
the amount which Payee could lawfully have contracted for, reserved, received,
retained or charged had the interest been calculated for the full term of the
obligations. On each day, if any, that the interest rate (the "Stated Rate")
called for under this Note or any other Debt Document exceeds the maximum
non-usurious rate, the rate at which interest shall accrue shall automatically
be fixed by operation of this sentence at the maximum non-usurious rate for that
day. Thereafter, interest shall accrue at the Stated Rate unless and until the
Stated Rate again exceeds the maximum non-usurious rate, in which case, the
provisions of the immediately preceding sentence shall again automatically
operate to limit the interest accrual rate to the maximum non-usurious rate. The
daily interest rates to be used in calculating interest at the maximum non-
usurious rate shall be determined by dividing the applicable maximum
non-usurious rate by the number of days in the calendar year for which such
calculation is being made. None of the terms and provisions contained in this
Note or in any other Debt Document which directly or indirectly relate to
interest shall ever be construed without reference to this paragraph, or be
construed to create a contract to pay for the use, forbearance or detention of
money at an interest rate in excess of the maximum non-usurious rate. If the
term of any obligation is shortened by reason of acceleration of maturity as a
result of any Default or by any other cause, or by reason of any required or
permitted prepayment, and if for that (or any other) reason Payee at any time,


                                   Page 2 of 4

<PAGE>

Promissory Note                             Master Security Agreement No.6081111
                                                                  Schedule No.03

including but not limited to, the stated maturity, is owed or receives (and/or
has received) interest in excess of interest calculated at the maximum
non-usurious rate, then and in any such event all of any such excess interest
shall be canceled automatically as of the date of such acceleration, prepayment
or other event which produces the excess, and, if such excess interest has been
paid to Payee, it shall be credited pro tanto against the then-outstanding
principal balance of Maker's obligations to Payee, effective as of the date or
dates when the event occurs which causes it to be excess interest, until such
excess is exhausted or all of such principal has been fully paid and satisfied,
whichever occurs first, and any remaining balance of such excess shall be
promptly refunded to its payor.

THE MAKER HEREBY UNCONDITIONALLY WAIVES ITS RIGHTS TO A JURY TRIAL OF ANY CLAIM
OR CAUSE OF ACTION BASED UPON OR ARISING OUT OF, DIRECTLY OR INDIRECTLY, THIS
NOTE, ANY OF THE RELATED DOCUMENTS, ANY DEALINGS BETWEEN MAKER AND PAYEE
RELATING TO THE SUBJECT MATTER OF THIS TRANSACTION OR ANY RELATED TRANSACTIONS,
AND/OR THE RELATIONSHIP THAT IS BEING ESTABLISHED BETWEEN MAKER AND PAYEE. THE
SCOPE OF THIS WAIVER IS INTENDED TO BE ALL ENCOMPASSING OF ANY AND ALL DISPUTES
THAT MAY BE FILED IN ANY COURT (INCLUDING, WITHOUT LIMITATION, CONTRACT CLAIMS,
TORT CLAIMS, BREACH OF DUTY CLAIMS, AND ALL OTHER COMMON LAW AND STATUTORY
CLAIMS.) THIS WAIVER IS IRREVOCABLE, MEANING THAT IT MAY NOT BE MODIFIED EITHER
ORALLY OR IN WRITING, AND THE WAIVER SHALL APPLY TO ANY SUBSEQUENT AMENDMENTS,
RENEWALS, SUPPLEMENTS OR MODIFICATIONS TO THIS NOTE, ANY RELATED DOCUMENTS, OR
TO ANY OTHER DOCUMENTS OR AGREEMENTS RELATING TO THIS TRANSACTION OR ANY RELATED
TRANSACTION. IN THE EVENT OF LITIGATION, THIS NOTE MAY BE FILED AS A WRITTEN
CONSENT TO A TRIAL BY THE COURT.

This Note and any Security Agreement constitute the entire agreement of the
Maker and Payee with respect to the subject matter hereof and supersedes all
prior understandings, agreements and representations, express or implied.

No variation or modification of this Note, or any waiver of any of its
provisions or conditions, shall be valid unless in writing and signed by an
authorized representative of Maker and Payee. Any such waiver, consent,
modification or change shall be effective only in the specific instance and for
the specific purpose given.

Any provision in this Note or any Security Agreement which is in conflict with
any statute, law or applicable rule shall be deemed omitted, modified or altered
to conform thereto.

Upon receipt of an affidavit of an officer of Payee as to the loss, theft,
destruction or mutilation of this Note or any Debt Document which is not of
public record, and, in the case of any such loss, theft, destruction or
mutilation, upon surrender and cancellation of such Note or other Debt Document,
Maker will issue, in lieu thereof, a replacement Note or other Debt Document in
the same principal amount thereof and otherwise of like tenor.

It is understood and agreed that this Note and all of the Debt Documents were
negotiated and have been or will be delivered to Payee in the Commonwealth of
Virginia, which State the parties agree has a substantial relationship to the
parties and to the underlying transactions embodied by this Note and the Debt
Documents. Maker agrees to furnish to Payee at Payee's office in Alexandria, VA,
all further instruments, certifications and documents to be furnished hereunder.
The parties also agree that if collateral is pledged to secure the debt
evidenced by this Note, that the state or states in which such collateral is
located each have a substantial relationship to the parties and to the
underlying transaction embodied by this Note and the Debt Documents.


                                  Page 3 of 4

<PAGE>

Promissory Note                             Master Security Agreement No.6081111
                                                                  Schedule No.03

MAKER AGREES THAT THE PAYEE OF THIS NOTE SHALL HAVE THE OPTION BY WHICH STATE
LAWS THIS NOTE SHALL BE GOVERNED AND CONSTRUED: (A) THE LAWS OF THE COMMONWEALTH
OF VIRGINIA; OR (B) IF COLLATERAL HAS BEEN PLEDGED TO SECURE THE DEBT EVIDENCED
BY THIS NOTE, THEN BY THE LAWS OF THE STATE OR STATES WHERE THE COLLATERAL IS
LOCATED, AT PAYEE'S OPTION. THIS CHOICE OF STATE LAWS IS EXCLUSIVE TO THE PAYEE
OF THIS NOTE. MAKER SHALL NOT HAVE ANY OPTION TO CHOOSE THE LAWS BY WHICH THIS
NOTE SHALL BE GOVERNED. MAKER AND GUARANTORS HEREBY CONSENT TO THE EXERCISE OF
JURISDICTION OVER IT BY ANY FEDERAL COURT SITTING IN VIRGINIA OR ANY VIRGINIA
COURT SELECTED BY PAYEE, FOR THE PURPOSES OF ANY AND ALL LEGAL PROCEEDINGS
ARISING OUT OF OR RELATING TO THE NOTE, THE LOAN AGREEMENT AND ALL OTHER
DOCUMENTS. MAKER AND GUARANTORS IRREVOCABLY WAIVE, TO THE FULLEST EXTENT
PERMITTED BY LAW, ANY OBJECTION WHICH IT MAY NOW OR HEREAFTER HAVE TO THE LAYING
OF VENUE OF ANY SUCH PROCEEDING BROUGHT IN ANY SUCH COURT, ANY CLAIM BASED ON
THE CONSOLIDATION OF PROCEEDINGS IN SUCH COURTS IN WHICH PROPER VENUE MAY LIE IN
DIVERGENT JURISDICTIONS, AND ANY CLAIM THAT ANY SUCH PROCEEDING BROUGHT IN ANY
SUCH COURT HAS BEEN BROUGHT IN AN INCONVENIENT FORUM. MAKER AND GUARANTORS
HEREBY IRREVOCABLY WAIVE, TO THE FULLEST EXTENT PERMITTED BY LAW, ANY AND ALL
RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO
THIS NOTE, THE OTHER DOCUMENTS OR THE TRANSACTIONS CONTEMPLATED THEREBY.

                                        athenahealth, Inc.


/s/ Monica Nendza                       By: /s/ Carl Byers
-------------------------------------       ------------------------------------
(Witness)                               Name: Carl Byers
Monica Nendza                           Title: CFO
(Print name)                            Federal Tax ID #: 04-3387530
311 Arsenal St Watertown, MA 02472      Address: 311 Arsenal Street
(Address)                                        Watertown, MA 02472


                                   Page 4 of 4
<PAGE>


Promissory Note                             Master Security Agreement No.6081111
                                                                  Schedule No.04

                                PROMISSORY NOTE
                    TO MASTER SECURITY AGREEMENT NO. 6081111
                                DECEMBER 15, 2006

FOR VALUE RECEIVED, athenahealth, Inc., a Delaware corporation, located at the
address stated below ("MAKER") promises to pay to the order of OXFORD FINANCE
CORPORATION or any subsequent holder hereof (each, a "PAYEE") at its office
located at 133 N. FAIRFAX STREET, ALEXANDRIA, VA 22314 or at such other place as
Payee or the holder hereof may designate, the principal sum of ONE MILLION, ONE
HUNDRED FIFTY-SEVEN THOUSAND, ONE HUNDRED FIFTY AND FORTY-EIGHT ONE-HUNDREDTHS
DOLLARS ($1,157,150.48), with interest on the unpaid principal balance, from the
date hereof through and including the dates of payment, at a fixed interest rate
of Ten and Forty-eight One-Hundredths Percent (10.48%) per annum, in thirty six
(36) consecutive monthly installments of principal and interest (each, a
"PERIODIC INSTALLMENT") as follows:

<TABLE>
<CAPTION>
Periodic
Installment        Amount
-----------   ---------------
<S>           <C>
1-36          $37,273.78 each
</TABLE>

and a final installment which shall be in the amount of the total outstanding
principal and interest, if any. The first Periodic Installment shall be due and
payable on or about December 15, 2006, and each of the following Periodic
Installments and the final installment shall be due and payable on the first day
of each succeeding month (each, a "PAYMENT DATE") beginning February 1, 2007.
Such installments have been calculated on the basis of a 360-day year of twelve
30-day months. Each payment may, at the option of the Payee, be calculated and
applied on an assumption that such payment would be made on its due date. Maker
agrees to pay any initial partial month interest payment from the date of this
Note to the first day of the following month ("Interim Interest").

The acceptance by Payee of any payment which is less than payment in full of all
amounts due and owing at such time shall not constitute a waiver of Payee's
right to receive payment in full at such time or at any prior or subsequent
time.

The Maker hereby expressly authorizes the Payee to insert the date value is
actually given in the blank space on the face hereof and on all related
documents pertaining hereto.

This Note may be secured by a security agreement, chattel mortgage, pledge
agreement or like instrument (each of which is hereinafter called a "SECURITY
AGREEMENT" AND ANY SECURITY AGREEMENT, THIS NOTE AND ANY OTHER DOCUMENT
EVIDENCING OR SECURING THIS LOAN IS HEREINAFTER CALLED A "DEBT DOCUMENT").

Time is of the essence hereof. If any installment or any other sum due under
this Note or any Security Agreement is not received within five (5) days of when
due, the Maker agrees to pay, in addition to the amount of each such installment
or other sum, a late payment charge of five percent (5%) of the amount of said
installment or other sum, but not exceeding any lawful maximum. If (i) Maker
fails to make payment of any amount due hereunder; or (ii) Maker is in default
under, or fails to perform under any term or condition contained in any Security
Agreement, then the entire principal sum remaining unpaid, together with all
accrued interest thereon and any other sum payable under this Note or any
Security Agreement, at the election of Payee, shall immediately become due and
payable, with interest thereon at the lesser of eighteen percent (18%) per annum
or the highest rate not prohibited by applicable law from the date of such
accelerated maturity until paid (both before and after any judgment).

For a period of ninety (90) days immediately following the date of closing of
either (i) Maker's initial public offering of its Common Stock or (ii) the
merger or consolidation of Maker with or the sale of a majority of Maker's
outstanding voting capital stock to an entity with a post-closing market
capitalization of at least $400 million, Maker shall be entitled to prepay in
full, but not in part, its entire Indebtedness hereunder by payment of the
entire Indebtedness plus an additional sum as a premium equal to the following
percentages of the remaining principal balance for the indicated period:


                                   Page 1 of 4

<PAGE>

Promissory Note                             Master Security Agreement No.6081111
                                                                  Schedule No.04

     From the date of this Note until the first anniversary of the date of this
     Note: three percent(3%)

     From the first annual anniversary date of this Note until the second annual
     anniversary date of this Note: two percent (2%)

     From the second annual anniversary date of this Note until the third annual
     anniversary date of this Note: one percent (1%)

At all other times and notwithstanding anything to the contrary contained herein
or in the Security Agreement, Maker may prepay in full, but not in part, its
entire Indebtedness hereunder by payment of the entire Indebtedness plus an
additional sum as a premium equal to the following percentages of the remaining
principal balance for the indicated period:

     From the date of this Note until the first anniversary of the date of this
     Note: six percent (6%)

     From the first annual anniversary date of this Note until the second annual
     anniversary date of this Note: four percent (4%)

     From the second annual anniversary date of this Note until the third annual
     anniversary date of this Note: two percent (2%)

The Maker and all sureties, endorsers, guarantors, or any others (each such
person, other than the Maker, an "Obligor") who may at any time become liable
for the payment hereof jointly and severally consent hereby to any and all
extensions of time, renewals, waivers or modifications of, and all substitutions
or releases of, security or of any party primarily or secondarily liable on this
Note or any Security Agreement or any term and provision of either, which may be
made, granted or consented to by Payee, and agree that suit may be brought and
maintained against any one or more of them, at the election of Payee without
joinder of any other as a party thereto, and that Payee shall not be required
first to foreclose, proceed against, or exhaust any security hereof in order to
enforce payment of this Note. The Maker and each Obligor hereby waives
presentment, demand for payment, notice of nonpayment, protest, notice of
protest, notice of dishonor, and all other notices in connection herewith, as
well as filing of suit (if permitted by law) and diligence in collecting this
Note or enforcing any of the security hereof, and agrees to pay (if and to the
extent permitted by law) all expenses incurred in collection, including Payee's
actual attorneys' fees.

Maker and Payee intend to strictly comply with all applicable federal and
Virginia laws, including applicable usury laws (or the usury laws of any
jurisdiction whose usury laws are deemed to apply to the Note or any other Debt
Document despite the intention and desire of the parties to apply the usury laws
of the Commonwealth of Virginia). Accordingly, the provisions of this paragraph
shall govern and control over every other provision of this Note or any other
Debt Document which conflicts or is inconsistent with this Section, even if such
provision declares that it controls. As used in this paragraph, the term
"interest" includes the aggregate of all charges, fees, benefits or other
compensation which constitute interest under applicable law, provided that, to
the maximum extent permitted by applicable law, (a) any non-principal payment
shall be characterized as an expense or as compensation for something other than
the use, forbearance or detention of money and not as interest, and (b) all
interest at any time contracted for, reserved, charged or received shall be
amortized, prorated, allocated and spread, in equal parts during the full term
of the obligations. In no event shall Maker or any other person be obligated to
pay, or Payee have any right or privilege to reserve, receive or retain, (a) any
interest in excess of the maximum amount of non-usurious interest permitted
under the laws of the Commonwealth of Virginia or the applicable laws (if any)
of the United States or of any other state, or (b) total interest in excess of
the amount which Payee could lawfully have contracted for, reserved, received,
retained or charged had the interest been calculated for the full term of the
obligations. On each day, if any, that the interest rate (the "Stated Rate")
called for under this Note or any other Debt Document exceeds the maximum
non-usurious rate, the rate at which interest shall accrue shall automatically
be fixed by operation of this sentence at the maximum non-usurious rate for that
day. Thereafter, interest shall accrue at the Stated Rate unless and until the
Stated Rate again exceeds the maximum non-usurious rate, in which case, the
provisions of the immediately preceding sentence shall again automatically
operate to limit the interest accrual rate to the maximum non-usurious rate. The
daily interest rates to be used in calculating interest at the maximum non-
usurious rate shall be determined by dividing the applicable maximum
non-usurious rate by the number of days in the calendar year for which such
calculation is being made. None of the terms and provisions contained in this
Note or in any other Debt Document which directly or indirectly relate to
interest shall ever be construed without reference to this paragraph, or be
construed to create a contract to pay for the use, forbearance or detention of
money at an interest rate in excess of the maximum non-usurious rate. If the
term of any obligation is shortened by reason of acceleration of maturity as a
result of any Default or by any other cause, or by reason of any required or
permitted prepayment, and if for that (or any other) reason Payee at any time,


                                  Page 2 of 4

<PAGE>

Promissory Note                             Master Security Agreement No.6081111
                                                                  Schedule No.04

including but not limited to, the stated maturity, is owed or receives (and/or
has received) interest in excess of interest calculated at the maximum
non-usurious rate, then and in any such event all of any such excess interest
shall be canceled automatically as of the date of such acceleration, prepayment
or other event which produces the excess, and, if such excess interest has been
paid to Payee, it shall be credited pro tanto against the then-outstanding
principal balance of Maker's obligations to Payee, effective as of the date or
dates when the event occurs which causes it to be excess interest, until such
excess is exhausted or all of such principal has been fully paid and satisfied,
whichever occurs first, and any remaining balance of such excess shall be
promptly refunded to its payor.

THE MAKER HEREBY UNCONDITIONALLY WAIVES ITS RIGHTS TO A JURY TRIAL OF ANY CLAIM
OR CAUSE OF ACTION BASED UPON OR ARISING OUT OF, DIRECTLY OR INDIRECTLY, THIS
NOTE, ANY OF THE RELATED DOCUMENTS, ANY DEALINGS BETWEEN MAKER AND PAYEE
RELATING TO THE SUBJECT MATTER OF THIS TRANSACTION OR ANY RELATED TRANSACTIONS,
AND/OR THE RELATIONSHIP THAT IS BEING ESTABLISHED BETWEEN MAKER AND PAYEE. THE
SCOPE OF THIS WAIVER IS INTENDED TO BE ALL ENCOMPASSING OF ANY AND ALL DISPUTES
THAT MAY BE FILED IN ANY COURT (INCLUDING, WITHOUT LIMITATION, CONTRACT CLAIMS,
TORT CLAIMS, BREACH OF DUTY CLAIMS, AND ALL OTHER COMMON LAW AND STATUTORY
CLAIMS.) THIS WAIVER IS IRREVOCABLE, MEANING THAT IT MAY NOT BE MODIFIED EITHER
ORALLY OR IN WRITING, AND THE WAIVER SHALL APPLY TO ANY SUBSEQUENT AMENDMENTS,
RENEWALS, SUPPLEMENTS OR MODIFICATIONS TO THIS NOTE, ANY RELATED DOCUMENTS, OR
TO ANY OTHER DOCUMENTS OR AGREEMENTS RELATING TO THIS TRANSACTION OR ANY RELATED
TRANSACTION. IN THE EVENT OF LITIGATION, THIS NOTE MAY BE FILED AS A WRITTEN
CONSENT TO A TRIAL BY THE COURT.

This Note and any Security Agreement constitute the entire agreement of the
Maker and Payee with respect to the subject matter hereof and supersedes all
prior understandings, agreements and representations, express or implied.

No variation or modification of this Note, or any waiver of any of its
provisions or conditions, shall be valid unless in writing and signed by an
authorized representative of Maker and Payee. Any such waiver, consent,
modification or change shall be effective only in the specific instance and for
the specific purpose given.

Any provision in this Note or any Security Agreement which is in conflict with
any statute, law or applicable rule shall be deemed omitted, modified or altered
to conform thereto.

Upon receipt of an affidavit of an officer of Payee as to the loss, theft,
destruction or mutilation of this Note or any Debt Document which is not of
public record, and, in the case of any such loss, theft, destruction or
mutilation, upon surrender and cancellation of such Note or other Debt Document,
Maker will issue, in lieu thereof, a replacement Note or other Debt Document in
the same principal amount thereof and otherwise of like tenor.

It is understood and agreed that this Note and all of the Debt Documents were
negotiated and have been or will be delivered to Payee in the Commonwealth of
Virginia, which State the parties agree has a substantial relationship to the
parties and to the underlying transactions embodied by this Note and the Debt
Documents. Maker agrees to furnish to Payee at Payee's office in Alexandria, VA,
all further instruments, certifications and documents to be furnished hereunder.
The parties also agree that if collateral is pledged to secure the debt
evidenced by this Note, that the state or states in which such collateral is
located each have a substantial relationship to the parties and to the
underlying transaction embodied by this Note and the Debt Documents.


                                  Page 3 of 4

<PAGE>

Promissory Note                             Master Security Agreement No.6081111
                                                                  Schedule No.04

MAKER AGREES THAT THE PAYEE OF THIS NOTE SHALL HAVE THE OPTION BY WHICH STATE
LAWS THIS NOTE SHALL BE GOVERNED AND CONSTRUED: (A) THE LAWS OF THE COMMONWEALTH
OF VIRGINIA; OR (B) IF COLLATERAL HAS BEEN PLEDGED TO SECURE THE DEBT EVIDENCED
BY THIS NOTE, THEN BY THE LAWS OF THE STATE OR STATES WHERE THE COLLATERAL IS
LOCATED, AT PAYEE'S OPTION. THIS CHOICE OF STATE LAWS IS EXCLUSIVE TO THE PAYEE
OF THIS NOTE. MAKER SHALL NOT HAVE ANY OPTION TO CHOOSE THE LAWS BY WHICH THIS
NOTE SHALL BE GOVERNED. MAKER AND GUARANTORS HEREBY CONSENT TO THE EXERCISE OF
JURISDICTION OVER IT BY ANY FEDERAL COURT SITTING IN VIRGINIA OR ANY VIRGINIA
COURT SELECTED BY PAYEE, FOR THE PURPOSES OF ANY AND ALL LEGAL PROCEEDINGS
ARISING OUT OF OR RELATING TO THE NOTE, THE LOAN AGREEMENT AND ALL OTHER
DOCUMENTS. MAKER AND GUARANTORS IRREVOCABLY WAIVE, TO THE FULLEST EXTENT
PERMITTED BY LAW, ANY OBJECTION WHICH IT MAY NOW OR HEREAFTER HAVE TO THE LAYING
OF VENUE OF ANY SUCH PROCEEDING BROUGHT IN ANY SUCH COURT, ANY CLAIM BASED ON
THE CONSOLIDATION OF PROCEEDINGS IN SUCH COURTS IN WHICH PROPER VENUE MAY LIE IN
DIVERGENT JURISDICTIONS, AND ANY CLAIM THAT ANY SUCH PROCEEDING BROUGHT IN ANY
SUCH COURT HAS BEEN BROUGHT IN AN INCONVENIENT FORUM. MAKER AND GUARANTORS
HEREBY IRREVOCABLY WAIVE, TO THE FULLEST EXTENT PERMITTED BY LAW, ANY AND ALL
RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO
THIS NOTE, THE OTHER DOCUMENTS OR THE TRANSACTIONS CONTEMPLATED THEREBY.

                                        athenahealth, Inc.


/s/ Monica Nendza                       By: /s/ Carl Byers
-------------------------------------       ------------------------------------
(Witness)                               Name: Carl Byers
Monica Nendza                           Title: CFO
(Print name)
311 Arsenal St Watertown, MA 02472      Federal Tax ID #: 04-3387530
(Address)
                                        Address: 311 Arsenal Street
                                                 Watertown, MA 02472


                                   Page 4 of 4
<PAGE>


Promissory Note                            Master Security Agreement No. 6081111
                                                                 Schedule No. 05

                                 PROMISSORY NOTE
                    TO MASTER SECURITY AGREEMENT NO. 6081111
                                  MARCH 19,2007

FOR VALUE RECEIVED, athenahealth, Inc., a Delaware corporation, located at the
address stated below ("MAKER") promises to pay to the order of OXFORD FINANCE
CORPORATION or any subsequent holder hereof (each, a "PAYEE") at its office
located at 133 N. FAIRFAX STREET, ALEXANDRIA, VA 22314 or at such other place as
Payee or the holder hereof may designate, the principal sum of FOUR HUNDRED
THOUSAND, SIX HUNDRED SEVENTY-SEVEN AND TWENTY-FIVE ONE-HUNDREDTHS DOLLARS
($400,677.25), with interest on the unpaid principal balance, from the date
hereof through and including the dates of payment, at a fixed interest rate of
Eleven and Fifty-One One-Hundredths Percent (11.51%) per annum, in thirty six
(36) consecutive monthly installments of principal and interest (each, a
"PERIODIC INSTALLMENT") as follows:

<TABLE>
<CAPTION>
Periodic
Installment        Amount
-----------   ---------------
<S>           <C>
1- 36         $13,089.09 each
</TABLE>

and a final installment which shall be in the amount of the total outstanding
principal and interest, if any. The first Periodic Installment shall be due and
payable on or about March 19, 2007, and each of the following Periodic
Installments and the final installment shall be due and payable on the first day
of each succeeding month (each, a "PAYMENT DATE") beginning May 1, 2007. Such
installments have been calculated on the basis of a 360-day year of twelve
30-day months. Each payment may, at the option of the Payee, be calculated and
applied on an assumption that such payment would be made on its due date. Maker
agrees to pay any initial partial month interest payment from the date of this
Note to the first day of the following month ("Interim Interest").

The acceptance by Payee of any payment which is less than payment in full of all
amounts due and owing at such time shall not constitute a waiver of Payee's
right to receive payment in full at such time or at any prior or subsequent
time.

The Maker hereby expressly authorizes the Payee to insert the date value is
actually given in the blank space on the face hereof and on all related
documents pertaining hereto.

This Note may be secured by a security agreement, chattel mortgage, pledge
agreement or like instrument (each of which is hereinafter called a "Security
Agreement" and any Security Agreement, this Note and any other document
evidencing or securing this loan is hereinafter called a "Debt Document").

Time is of the essence hereof. If any installment or any other sum due under
this Note or any Security Agreement is not received within five (5) days of when
due, the Maker agrees to pay, in addition to the amount of each such installment
or other sum, a late payment charge of five percent (5%) of the amount of said
installment or other sum, but not exceeding any lawful maximum. If (i) Maker
fails to make payment of any amount due hereunder; or (ii) Maker is in default
under, or fails to perform under any term or condition contained in any Security
Agreement, then the entire principal sum remaining unpaid, together with all
accrued interest thereon and any other sum payable under this Note or any
Security Agreement, at the election of Payee, shall immediately become due and
payable, with interest thereon at the lesser of eighteen percent (18%) per annum
or the highest rate not prohibited by applicable law from the date of such
accelerated maturity until paid (both before and after any judgment).

For a period of ninety (90) days immediately following the date of closing of
either (i) Maker's initial public offering of its Common Stock or (ii) the
merger or consolidation of Maker with or the sale of a majority of Maker's
outstanding voting capital stock to an entity with a post-closing market
capitalization of at least $400 million, Maker shall be entitled to prepay in
full, but not in part, its entire Indebtedness hereunder by payment of the
entire Indebtedness plus an additional sum as a premium equal to the following
percentages of the remaining principal balance for the indicated period:


                                   Page 1 of 4

<PAGE>

Promissory Note                            Master Security Agreement No. 6081111
                                                                 Schedule No. 05

     From the date of this Note until the first anniversary of the date of this
     Note: three percent (3%)

     From the first annual anniversary date of this Note until the second annual
     anniversary date of this Note: two percent (2%)

     From the second annual anniversary date of this Note until the third annual
     anniversary date of this Note: one percent (1%)

At all other times and notwithstanding anything to the contrary contained herein
or in the Security Agreement, Maker may prepay in full, but not in part, its
entire Indebtedness hereunder by payment of the entire Indebtedness plus an
additional sum as a premium equal to the following percentages of the remaining
principal balance for the indicated period:

     From the date of this Note until the first anniversary of the date of this
     Note: six percent (6%)

     From the first annual anniversary date of this Note until the second annual
     anniversary date of this Note: four percent (4%)

     From the second annual anniversary date of this Note until the third annual
     anniversary date of this Note: two percent (2%)

The Maker and all sureties, endorsers, guarantors, or any others (each such
person, other than the Maker, an "Obligor") who may at any time become liable
for the payment hereof jointly and severally consent hereby to any and all
extensions of time, renewals, waivers or modifications of, and all substitutions
or releases of, security or of any party primarily or secondarily liable on this
Note or any Security Agreement or any term and provision of either, which may be
made, granted or consented to by Payee, and agree that suit may be brought and
maintained against any one or more of them, at the election of Payee without
joinder of any other as a party thereto, and that Payee shall not be required
first to foreclose, proceed against, or exhaust any security hereof in order to
enforce payment of this Note. The Maker and each Obligor hereby waives
presentment, demand for payment, notice of nonpayment, protest, notice of
protest, notice of dishonor, and all other notices in connection herewith, as
well as filing of suit (if permitted by law) and diligence in collecting this
Note or enforcing any of the security hereof and agrees to pay (if and to the
extent permitted by law) all expenses incurred in collection, including Payee's
actual attorneys' fees.

Maker and Payee intend to strictly comply with all applicable federal and
Virginia laws, including applicable usury laws (or the usury laws of any
jurisdiction whose usury laws are deemed to apply to the Note or any other Debt
Document despite the intention and desire of the parties to apply the usury laws
of the Commonwealth of Virginia). Accordingly, the provisions of this paragraph
shall govern and control over every other provision of this Note or any other
Debt Document which conflicts or is inconsistent with this Section, even if such
provision declares that it controls. As used in this paragraph, the term
"INTEREST" includes the aggregate of all charges, fees, benefits or other
compensation which constitute interest under applicable law, provided that, to
the maximum extent permitted by applicable law, (a) any non-principal payment
shall be characterized as an expense or as compensation for something other than
the use, forbearance or detention of money and not as interest, and (b) all
interest at any time contracted for, reserved, charged or received shall be
amortized, prorated, allocated and spread, in equal parts during the full term
of the obligations. In no event shall Maker or any other person be obligated to
pay, or Payee have any right or privilege to reserve, receive or retain, (a) any
interest in excess of the maximum amount of non-usurious interest permitted
under the laws of the Commonwealth of Virginia or the applicable laws (if any)
of the United States or of any other state, or (b) total interest in excess of
the amount which Payee could lawfully have contracted for, reserved, received,
retained or charged had the interest been calculated for the full term of the
obligations. On each day, if any, that the interest rate (the "Stated Rate")
called for under this Note or any other Debt Document exceeds the maximum
non-usurious rate, the rate at which interest shall accrue shall automatically
be fixed by operation of this sentence at the maximum non-usurious rate for that
day. Thereafter, interest shall accrue at the Stated Rate unless and until the
Stated Rate again exceeds the maximum non-usurious rate, in which case, the
provisions of the immediately preceding sentence shall again automatically
operate to limit the interest accrual rate to the maximum non-usurious rate. The
daily interest rates to be used in calculating interest at the maximum
non-usurious rate shall be determined by dividing the applicable maximum
non-usurious rate by the number of days in the calendar year for which such
calculation is being made. None of the terms and provisions contained in this
Note or in any other Debt Document which directly or indirectly relate to
interest shall ever be construed without reference to this paragraph, or be
construed to create a contract to pay for the use, forbearance or detention of
money at an interest rate in excess of the maximum non-usurious rate. If the
term of any obligation is shortened by reason of acceleration of maturity as a
result of any Default or by any other cause, or by reason of any required or
permitted prepayment, and if for that (or any other) reason Payee at any time,


                                   Page 2 of 4

<PAGE>

Promissory Note                            Master Security Agreement No. 6081111
                                                                 Schedule No. 05

including but not limited to, the stated maturity, is owed or receives (and/or
has received) interest in excess of interest calculated at the maximum
non-usurious rate, then and in any such event all of any such excess interest
shall be canceled automatically as of the date of such acceleration, prepayment
or other event which produces the excess, and, if such excess interest has been
paid to Payee, it shall be credited pro tanto against the then-outstanding
principal balance of Maker's obligations to Payee, effective as of the date or
dates when the event occurs which causes it to be excess interest, until such
excess is exhausted or all of such principal has been fully paid and satisfied,
whichever occurs first, and any remaining balance of such excess shall be
promptly refunded to its payor.

THE MAKER HEREBY UNCONDITIONALLY WAIVES ITS RIGHTS TO A JURY TRIAL OF ANY CLAIM
OR CAUSE OF ACTION BASED UPON OR ARISING OUT OF, DIRECTLY OR INDIRECTLY, THIS
NOTE, ANY OF THE RELATED DOCUMENTS, ANY DEALINGS BETWEEN MAKER AND PAYEE
RELATING TO THE SUBJECT MATTER OF THIS TRANSACTION OR ANY RELATED TRANSACTIONS,
AND/OR THE RELATIONSHIP THAT IS BEING ESTABLISHED BETWEEN MAKER AND PAYEE. THE
SCOPE OF THIS WAIVER IS INTENDED TO BE ALL ENCOMPASSING OF ANY AND ALL DISPUTES
THAT MAY BE FILED IN ANY COURT (INCLUDING, WITHOUT LIMITATION, CONTRACT CLAIMS,
TORT CLAIMS, BREACH OF DUTY CLAIMS, AND ALL OTHER COMMON LAW AND STATUTORY
CLAIMS.) THIS WAIVER IS IRREVOCABLE, MEANING THAT IT MAY NOT BE MODIFIED EITHER
ORALLY OR IN WRITING, AND THE WAIVER SHALL APPLY TO ANY SUBSEQUENT AMENDMENTS,
RENEWALS, SUPPLEMENTS OR MODIFICATIONS TO THIS NOTE, ANY RELATED DOCUMENTS, OR
TO ANY OTHER DOCUMENTS OR AGREEMENTS RELATING TO THIS TRANSACTION OR ANY RELATED
TRANSACTION. IN THE EVENT OF LITIGATION, THIS NOTE MAY BE FILED AS A WRITTEN
CONSENT TO A TRIAL BY THE COURT.

This Note and any Security Agreement constitute the entire agreement of the
Maker and Payee with respect to the subject matter hereof and supersedes all
prior understandings, agreements and representations, express or implied.

No variation or modification of this Note, or any waiver of any of its
provisions or conditions, shall be valid unless in writing and signed by an
authorized representative of Maker and Payee. Any such waiver, consent,
modification or change shall be effective only in the specific instance and for
the specific purpose given.

Any provision in this Note or any Security Agreement which is in conflict with
any statute, law or applicable rule shall be deemed omitted, modified or altered
to conform thereto.

Upon receipt of an affidavit of an officer of Payee as to the loss, theft,
destruction or mutilation of this Note or any Debt Document which is not of
public record, and, in the case of any such loss, theft, destruction or
mutilation, upon surrender and cancellation of such Note or other Debt Document,
Maker will issue, in lieu thereof, a replacement Note or other Debt Document in
the same principal amount thereof and otherwise of like tenor.

It is understood and agreed that this Note and all of the Debt Documents were
negotiated and have been or will be delivered to Payee in the Commonwealth of
Virginia, which State the parties agree has a substantial relationship to the
parties and to the underlying transactions embodied by this Note and the Debt
Documents. Maker agrees to furnish to Payee at Payee's office in Alexandria, VA,
all further instruments, certifications and documents to be furnished hereunder.
The parties also agree that if collateral is pledged to secure the debt
evidenced by this Note, that the state or states in which such collateral is
located each have a substantial relationship to the parties and to the
underlying transaction embodied by this Note and the Debt Documents.


                                   Page 3 of 4

<PAGE>

Promissory Note                            Master Security Agreement No. 6081111
                                                                 Schedule No. 05

MAKER AGREES THAT THE PAYEE OF THIS NOTE SHALL HAVE THE OPTION BY WHICH STATE
LAWS THIS NOTE SHALL BE GOVERNED AND CONSTRUED: (A) THE LAWS OF THE COMMONWEALTH
OF VIRGINIA; OR (B) IF COLLATERAL HAS BEEN PLEDGED TO SECURE THE DEBT EVIDENCED
BY THIS NOTE, THEN BY THE LAWS OF THE STATE OR STATES WHERE THE COLLATERAL IS
LOCATED, AT PAYEE'S OPTION. THIS CHOICE OF STATE LAWS IS EXCLUSIVE TO THE PAYEE
OF THIS NOTE. MAKER SHALL NOT HAVE ANY OPTION TO CHOOSE THE LAWS BY WHICH THIS
NOTE SHALL BE GOVERNED. MAKER AND GUARANTORS HEREBY CONSENT TO THE EXERCISE OF
JURISDICTION OVER IT BY ANY FEDERAL COURT SITTING IN VIRGINIA OR ANY VIRGINIA
COURT SELECTED BY PAYEE, FOR THE PURPOSES OF ANY AND ALL LEGAL PROCEEDINGS
ARISING OUT OF OR RELATING TO THE NOTE, THE LOAN AGREEMENT AND ALL OTHER
DOCUMENTS. MAKER AND GUARANTORS IRREVOCABLY WAIVE, TO THE FULLEST EXTENT
PERMITTED BY LAW, ANY OBJECTION WHICH IT MAY NOW OR HEREAFTER HAVE TO THE LAYING
OF VENUE OF ANY SUCH PROCEEDING BROUGHT IN ANY SUCH COURT, ANY CLAIM BASED ON
THE CONSOLIDATION OF PROCEEDINGS IN SUCH COURTS IN WHICH PROPER VENUE MAY LIE IN
DIVERGENT JURISDICTIONS, AND ANY CLAIM THAT ANY SUCH PROCEEDING BROUGHT IN ANY
SUCH COURT HAS BEEN BROUGHT IN AN INCONVENIENT FORUM. MAKER AND GUARANTORS
HEREBY IRREVOCABLY WAIVE, TO THE FULLEST EXTENT PERMITTED BY LAW, ANY AND ALL
RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO
THIS NOTE, THE OTHER DOCUMENTS OR THE TRANSACTIONS CONTEMPLATED THEREBY.

                                        athenahealth, Inc.


/s/ Monica Nendza                       By: /s/ Carl Byers
-------------------------------------       ------------------------------------
(Witness)                               Name: Carl Byers
Monica Nendza                           Title: CFO
(Print name)
311 Arsenal St Watertown, MA 02472      Federal Tax ID #: 04-3387530
(Address)
                                        Address: 311 Arsenal Street
                                                 Watertown, MA 02472


                                   Page 4 of 4