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                                                                    EXHIBIT 3.03

                          CERTIFICATE OF DESIGNATION

                                      of

                SERIES A NON-VOTING CONVERTIBLE PREFERRED STOCK

                                      of

                              AT HOME CORPORATION

                        (Pursuant to Section 151 of the

                       Delaware General Corporation Law)

                       ---------------------------------

     At Home Corporation, a Delaware corporation (the "Company"), does hereby
certify that pursuant to the authority granted to and vested in the Board of
Directors of the Company (the "Board of Directors" or the "Board") in accordance
with the provisions of Article IV, Section C of the Fifth Amended and Restated
Certificate of Incorporation of the Company, and in accordance with the
provisions of Section 151 of the Delaware General Corporation Law, the Company's
Board of Directors has duly adopted the following resolutions creating a series
of Preferred Stock, par value $0.01 per share ("Preferred Stock"), of the
Company designated as Series A Non-Voting Convertible Preferred Stock.

     RESOLVED, that the Company hereby designates and creates a series of
Preferred Stock of the Company and hereby states the designation and number of
shares, and fixes the relative rights, preferences, and limitations thereof as
follows:

          A.      Designation and Amount.  Of the 9,650,000 shares of Preferred
                  ----------------------
Stock authorized to be issued by the Company, 10,673.549 shares shall be
designated as "Series A Non-Voting Convertible Preferred Stock" ("Series A
Preferred Stock").  Such number of shares may be increased or decreased by
resolution of the Board of Directors; provided, that no decrease shall reduce
                                      --------
the number of shares of Series A Preferred Stock to a number less than the
number of shares then outstanding plus the number of shares reserved for
issuance upon the exercise of outstanding options, rights or warrants or upon
the conversion of any outstanding securities issued by the Company convertible
into Series A Preferred Stock.

          B.      Rights, Preferences and Restrictions of Preferred Stock.  The
                  -------------------------------------------------------
rights, preferences, restrictions and other matters relating to the Series A
Preferred Stock are as follows:

          1.      Dividends and Distributions.
                  ---------------------------

          (a)     Subject to the rights of the holders of any shares of any
series of Preferred Stock (or any other stock) ranking prior and superior to the
Series A Preferred Stock with respect to dividends, and subject to Section
5(c)(ii) hereof, the holders of shares of Series A Preferred Stock shall be
entitled to receive, when, as and if declared by the Board of Directors out of
funds legally available for the purpose, non-cumulative dividends in an amount
(if any) per share (rounded to the nearest cent), subject to the provision for
adjustment hereinafter set forth, equal to 1000 times the aggregate per share
amount of all cash dividends, and 1000 times the aggregate per share amount
(payable in kind) of all non-cash dividends or other distributions, other than a
dividend payable in shares of Series A Common Stock, par

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value $0.01 per share (the "Common Stock"), of the Company, or a subdivision of
the outstanding shares of Common Stock (by reclassification or otherwise),
declared on the Common Stock. In the event the Company shall at any time declare
or pay any dividend on the Common Stock payable in shares of Common Stock, or
effect a subdivision or combination or consolidation of the outstanding shares
of Common Stock (by reclassification or otherwise than by payment of a dividend
in shares of Common Stock) into a greater or lesser number of shares of Common
Stock, then in each such case the amount to which holders of shares of Series A
Preferred Stock were entitled immediately prior to such event under the
preceding sentence shall be adjusted by multiplying such amount by a fraction,
the numerator of which is the number of shares of Common Stock outstanding
immediately after such event and the denominator of which is the number of
shares of Common Stock that were outstanding immediately prior to such event.

          (b)     The Company shall declare a dividend or distribution on the
Series A Preferred Stock as provided in subsection (a) of this Section at the
same time it declares a dividend or distribution on the Common Stock (other than
a dividend payable in shares of Common Stock). The Board of Directors shall fix
a record date for the determination of holders of shares of Series A Preferred
Stock entitled to receive payment of a dividend or distribution declared
thereon, which record date shall be not more than 60 days prior to the date
fixed for the payment thereof.

          (c)     Dividends payable pursuant to subsection (a) of this Section
shall not be mandatory or cumulative (except as provided in subsection (b) of
this Section) and no rights or interest shall accrue to the holders of the
Series A Preferred Stock by reason of the fact that the Company shall fail to
declare or pay dividends on the Preferred Stock in any amount in any calendar
year or any fiscal year of the Company, whether or not earnings of the Company
in any calendar year or fiscal year were sufficient to pay such dividends in
whole or in part.

          (d)     Except as provided in this Section 1, holders of the Preferred
Stock shall not be entitled to receive any dividends.

          2.      Voting Rights. Except as otherwise provided by law, holders of
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Series A Preferred Stock shall have no voting rights and their consent shall not
be required for taking any corporate action.

          3.      Reacquired and Converted Shares. Any shares of Series A
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Preferred Stock purchased, received upon conversion or otherwise acquired by the
Company in any manner whatsoever shall be retired and canceled promptly after
the acquisition thereof and shall not be reissued.

          4.      Liquidation, Dissolution or Winding Up.
                  --------------------------------------

          (a)     Upon any liquidation, dissolution or winding up of the
Company, the holders of shares of Series A Preferred Stock shall be entitled to
receive an aggregate amount per share, subject to the provision for adjustment
hereinafter set forth, equal to 1000 times the aggregate amount to be
distributed per share to holders of shares of Common Stock, on a pro rata pari
passu basis with the Common Stock, plus an amount equal to any declared but
unpaid dividends. In the event the Company shall at any time declare or pay any
dividend on the Common Stock payable in shares of Common Stock, or effect a
subdivision or combination or consolidation of the outstanding shares of Common
Stock (by reclassification or otherwise than by payment of a dividend in shares
of Common Stock) into a greater or lesser number of shares of Common Stock, then
in each such case the aggregate amount to which holders of shares of Series A
Preferred Stock were entitled immediately prior to such event under the
preceding sentence shall be adjusted by multiplying such amount by a fraction
the numerator of which is the

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number of shares of Common Stock outstanding immediately after such event and
the denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event.

          (b)     The foregoing rights upon liquidation, dissolution or winding
up provided to the holders of Series A Preferred Stock shall be subject to the
rights of the holders of any other series of Preferred Stock (or any other
stock) ranking prior and superior to the Series A Preferred Stock upon
liquidation, dissolution or winding up.

          5.      Conversion Rights. The outstanding shares of Series A
                  -----------------
Preferred Stock shall be convertible into Common Stock as follows:

          (a)     Right to Convert. Subject to subsection (c), each share of
                  ----------------
Series A Preferred Stock shall become converted into the right to receive 1000
shares of Common Stock (the "Conversion Ratio") at the office of the Company or
any transfer agent for the Series A Preferred Stock, pursuant to the following
schedule: (i) 5,568.098 shares of Series A Preferred Stock (the "Reserved
Shares") on the two year anniversary of the date of original issuance of the
Series A Preferred Stock, (ii) 500 shares (the "Monthly Conversion Amount") of
Series A Preferred Stock on the date 30 days following the date of original
issuance of the Series A Preferred Stock, and (iii) excluding all Reserved
Shares, the Monthly Conversion Amount of Series A Preferred Stock on the
completion of each successive 30-day period following the initial 30-day period.
Notwithstanding the foregoing provisions of this Section 5(a), no shares of
Series A Preferred Stock held by a holder of Series A Preferred Stock who
transfers shares of Series A Preferred Stock to a Charitable Organization (as
such term is defined in Section 5(i)), which shares of Series A Preferred Stock
automatically convert into the right to receive shares of Common Stock pursuant
to Section 5(i) (such shares of Common Stock, the "Converted Shares"), shall
convert into the right to receive shares of Common Stock pursuant to the
schedule described in this Section 5(a) until the cumulative aggregate number of
shares of Common Stock that would have been issued upon conversion of such
transferred shares of Series A Preferred Stock pursuant to the schedule
described in this Section 5(a) equals the aggregate number of Converted Shares.
The initial Conversion Ratio of the Series A Preferred Stock shall be subject to
adjustment as hereinafter provided.

          (b)     Mechanics of Conversion.  No fractional shares of Common Stock
                  -----------------------
shall be issued upon conversion of Series A Preferred Stock.  In lieu of any
fractional shares to which the holder would otherwise be entitled, the Company
shall pay cash equal to the fair market value of such fractional interest as
determined by the Company's Board of Directors.  Before any holder of Series A
Preferred Stock shall be entitled to receive any certificates for the whole
shares of Common Stock issuable upon conversion of Series A Preferred Stock
(including, without limitation, any conversion pursuant to Section 5(i)), such
holder shall (i) deliver a certificate or certificates representing shares of
Series A Preferred Stock, if such stock is certificated, or (ii) deliver written
instructions to convert a number of Series A Preferred Stock, if such holder's
shares of Series A Preferred Stock are represented by an interest in a global
security, in each case, which shares of Series A Preferred Stock shall have
become converted into the right to receive shares of Common Stock pursuant to
the schedule set forth in Section 5(a), or the terms of Section 5(i), to the
Company at the office of the Company or of any transfer agent for the Series A
Preferred Stock.  The Company shall, as soon as practicable after such delivery,
issue and deliver at such office to such holder of Series A Preferred Stock, a
certificate or certificates for the number of shares of Common Stock to which
the holder shall be entitled as aforesaid and a check payable to the holder in
the amount of any cash amounts payable as the result of a conversion into
fractional shares of Common Stock.  Such conversion shall be deemed to have been
made immediately prior to the close of business on the date such certificate or
certificates are delivered, and the person or persons entitled to receive the
shares of Common Stock issuable upon such conversion shall be treated for all
purposes as the record holder or holders of such shares of Common Stock on such
date.

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          (c)     Adjustments to Conversion Ratio for Certain Diluting Issues.
                  -----------------------------------------------------------

          (i)     Adjustments for Dividends, Splits, Subdivisions, Combinations
                  -------------------------------------------------------------
or Consolidation of Common Stock. In the event the outstanding shares of Common
-----------------------------
Stock shall be increased by stock dividend payable in Common Stock, stock split,
subdivision, or other similar transaction into a greater number of shares of
Common Stock, the Conversion Ratio of the Series A Preferred Stock then in
effect shall, concurrently with the effectiveness of such event, be increased
proportionally.  In the event the outstanding shares of Common Stock shall be
decreased by reverse stock split, combination, consolidation, or other similar
transaction into a lesser number of shares of Common Stock, the Conversion Ratio
of the Series A Preferred Stock then in effect shall, concurrently with the
effectiveness of such event, be decreased proportionally.

          (ii)    Adjustments for Other Distributions. In the event the Company
                  -----------------------------------
at any time or from time to time makes, or fixes a record date for the
determination of holders of Common Stock entitled to receive any distribution
payable in securities of the Company other than shares of Common Stock and other
than any distribution which results in the payment of a dividend described in
Section 1, then and in each such event provision shall be made so that the
holders of Series A Preferred Stock shall receive upon conversion thereof, in
addition to the number of shares of Common Stock receivable thereupon, the
amount of securities of the Company which they would have received had their
Series A Preferred Stock been converted into Common Stock on the date of such
event and had they thereafter, during the period from the date of such event to
and including the date of conversion, retained such securities receivable by
them as aforesaid during such period, subject to all other adjustments called
for during such period under this Section 5 with respect to the rights of the
holders of the Series A Preferred Stock.

          (iii)   Adjustments for Reclassification, Exchange and Substitution.
                  -----------------------------------------------------------
If the Common Stock issuable upon conversion of the Series A Preferred Stock
shall be changed into the same or a different number of shares of any other
class or classes of stock, whether by capital reorganization, reclassification,
or otherwise (other than a subdivision or combination of shares provided for
above), then following the effectiveness of such reorganization or
reclassification the Series A Preferred Stock shall be convertible into, in lieu
of the number of shares of Common Stock which the holders would otherwise have
been entitled to receive, a number of shares of such other class or classes of
stock equivalent to the number of shares of Common Stock that would have been
subject to receipt by the holders upon conversion of such Series A Preferred
Stock immediately before that change.

          (iv)    Monthly Conversion Amount. In the event of any adjustment to
                  -------------------------
the Conversion Ratio pursuant to this Section 5, the Monthly Conversion Amount
shall be appropriately and proportionately adjusted.

          (d)     No Impairment.  Except as provided in Section 5, the Company
                  -------------
will not, by amendment of its Certificate of Incorporation or through any
reorganization, transfer of assets, consolidation, merger, dissolution, issue or
sale of securities, or any other voluntary action, avoid or seek to avoid the
observance or performance of any of the terms to be observed or performed
hereunder by the Company but will at all times in good faith assist in the
carrying out of all the provisions of this Section 5 and in the taking of all
such action as may be necessary or appropriate in order to protect the
conversion rights of the holders of the Series A Preferred Stock against
impairment.

          (e)     Certificate as to Adjustments.  Upon the occurrence of each
                  -----------------------------
adjustment or readjustment of the Conversion Ratio for the Series A Preferred
Stock pursuant to this Section 5, the Company at its expense shall promptly
compute such adjustment or readjustment in accordance with the terms hereof and
furnish to each holder of Series A Preferred Stock a certificate setting forth
such

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adjustment or readjustment and showing in detail the facts upon which such
adjustment or readjustment is based. The Company shall, upon the written request
at any time of any holder of Series A Preferred Stock, furnish or cause to be
furnished to such holder a like certificate setting forth (i) such adjustments
and readjustments, (ii) the Conversion Ratio at the time in effect, and (iii)
the number of shares of Common Stock and the amount, if any, of other property
which at the time would be received upon the conversion of the Series A
Preferred Stock.

          (f)     Notices of Record Date.  In the event that this Company shall
                  ----------------------
propose at any time:

          (i)     to declare any dividend or distribution upon its Common Stock,
whether in cash, property, stock, or other securities, whether or not a regular
cash dividend and whether or not out of earnings or earned surplus;

          (ii)    to offer for subscription pro rata to the holders of any class
or series of its stock any additional shares of stock of any class or series or
other rights;

          (iii)   to effect any reclassification or recapitalization of its
Common Stock outstanding involving a change in the Common Stock; or

          (iv)    to merge or consolidate with or into any other corporation, or
sell, lease, or convey all or substantially all its property or business, or to
liquidate, dissolve, or wind up;

          then, in connection with each such event, this Company shall send to
the holders of Series A Preferred Stock:

          (1)     at least 10 days prior written notice of the date on which a
record shall be taken for such dividend, distribution or subscription rights
(and specifying the date on which the holders of Common Stock shall be entitled
thereto) or for determining rights to vote in respect of the matters referred to
in (iii) and (iv) above; and

          (2)     in the case of the matters referred to in (iii) and (iv)
above, at least 20 days' prior written notice of the date when the same shall
take place (and specifying the date on which the holders of Common Stock shall
be entitled to exchange their Common Stock for securities or other property
deliverable upon the occurrence of such event or the record date for the
determination of such holders if such record date is earlier).

          Each such written notice shall be delivered personally, or given by
first class mail, postage prepaid, addressed to the holders of the Series A
Preferred Stock at the address for each such holder as shown on the books of
this Company.

          (g)     Issue Taxes.  The Company shall pay any and all issue and
                  -----------
other taxes (other than income taxes) that may be payable in respect of any
issue or delivery of shares of Common Stock on conversion of shares of Series A
Preferred Stock pursuant hereto; provided, however, that the Company shall not
be obligated to pay any transfer taxes resulting from any transfer requested by
any holder in connection with any such conversion.

          (h)     Reservation of Stock Issuable Upon Conversion. The Company
                  ---------------------------------------------
shall at all times reserve and keep available out of its authorized but unissued
shares of Common Stock, solely for the purpose of effecting the conversion of
the shares of the Series A Preferred Stock such number of its shares of Common
Stock as shall from time to time be sufficient to effect the conversion of all
outstanding shares of Series A Preferred Stock; and if at any time the number of
authorized but unissued

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shares of Common Stock shall not be sufficient to effect the conversion of all
then outstanding shares of the Series A Preferred Stock, the Company will take
such corporate action as may, in the opinion of its counsel, be necessary to
increase its authorized but unissued shares of Common Stock to such number of
shares as shall be sufficient for such purpose, including, without limitation,
engaging in best efforts to obtain the requisite stockholder approval of any
necessary amendment to its Certificate of Incorporation.


          (i)     Acceleration of Conversion.
                  --------------------------

          (i)     Upon the close of business on the date on which the Series B
Common Stock Directors are no longer entitled to exercise the Special Director
Approval Right, all shares of Series A Preferred Stock, other than Reserved
Shares, then outstanding shall automatically be converted into the right to
receive shares of Common Stock according to the Conversion Ratio then in effect.

          (ii)    Upon the irrevocable transfer of shares of Series A Preferred
Stock, other than Reserved Shares, not to exceed in the aggregate, together with
all such prior transfers, 1,418.2632 shares of Series A Preferred Stock, by an
initial holder of such shares of Series A Preferred Stock to an institution
qualified as tax exempt under Section 501(a) of the Code, as described in
501(c)(3) of the Internal Revenue Code of 1986, as amended (a "Charitable
Organization"), such transferred shares of Series A Preferred Stock shall, upon
the close of business on the date of such transfer, automatically be converted
into the right to receive shares of Common Stock according to the Conversion
Ratio then in effect.

          6.      Consolidation, Merger, etc. In case the Company shall enter
                  --------------------------
into any consolidation, merger, combination or other transaction in which the
shares of Common Stock are exchanged for or changed into other stock or
securities, cash and/or other property, then in any such case each share of
Series A Preferred Stock shall at the same time be similarly exchanged or
changed into an amount per share, subject to the provision for adjustment
hereinafter set forth, equal to 1000 times the aggregate amount of stock,
securities, cash and/or any other property (payable in kind), as the case may
be, into which or for which each share of Common Stock is changed or exchanged.
In the event the Company shall at any time declare or pay any dividend on the
Common Stock payable in shares of Common Stock, or effect a subdivision or
combination or consolidation of the outstanding shares of Common Stock (by
reclassification or otherwise than by payment of a dividend in shares of Common
Stock) into a greater or lesser number of shares of Common Stock, then in each
such case the amount set forth in the preceding sentence with respect to the
exchange or change of shares of Series A Preferred Stock shall be adjusted by
multiplying such amount by a fraction, the numerator of which is the number of
shares of Common Stock outstanding immediately after such event and the
denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event.

          7.      No Redemption. The shares of Series A Preferred Stock shall
                  -------------
not be redeemable.

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     IN WITNESS WHEREOF, this Certificate of Designation is executed on behalf
of the Company by its General Counsel and Secretary this 13th day of December,
1999.


                                 AT HOME CORPORATION


                                 By:  /s/ David G. Pine
                                    --------------------------------------------
                                    David G. Pine, General Counsel and Secretary

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