<PAGE>

                                                                     Exhibit 4.2

                         REGISTRATION RIGHTS AGREEMENT
                         -----------------------------

          Registration Rights Agreement, dated as of July 22, 1999, by and among
Mastech Corporation, a Pennsylvania corporation ("Company"), and GE Capital
Equity Investments, Inc., a Delaware corporation ("GE Capital" or "Purchaser").

                             W I T N E S S E T H :
                             -------------------

          WHEREAS, Company and Purchaser have entered into that certain Purchase
Agreement, dated as of July 22, 1999 (the "Purchase Agreement"), pursuant to
which Company has agreed to issue and sell to Purchaser, and Purchaser has
agreed to purchase from Company, a senior convertible note in the original
principal amount of $30,000,000 ("Convertible Note"); and

          WHEREAS, in order to induce Purchaser to enter into the Purchase
Agreement and to purchase the Convertible Note, Company has agreed to provide
registration rights with respect thereto;

          NOW, THEREFORE, in consideration of the premises and the covenants
hereinafter contained, it is agreed as follows:

          1. Definitions. Unless otherwise defined herein, terms used herein
             ------------
shall have the meaning ascribed to them in the Purchase Agreement, and the
following shall have the following respective meanings (such meanings being
equally applicable to both the singular and plural form of the terms defined):

          "Agreement" shall mean this Registration Rights Agreement, including
all amendments, modifications and supplements and any exhibits or schedules to
any of the foregoing, and shall refer to the Agreement as the same may be in
effect at the time such reference becomes operative.

          "Conversion Shares" shall mean shares of Common Stock issued upon
conversion of the of Convertible Note.

          "Holder" shall mean the holder of Conversion Shares or of the
Convertible Note.

          "Incidental Registration" shall have the meaning ascribed to it in
Section 3.

          "Majority Holders" shall mean Holders holding at the time, the
Convertible Note or Conversion Shares representing more than 50% of the sum of
(x) all then outstanding Conversion Shares and (y) all shares of Common Stock
issuable to the holders of then-outstanding Convertible Note upon the conversion
thereof.
<PAGE>

          "NASD" shall mean the National Association of Securities Dealers,
Inc., or any successor corporation thereto.

          "Registrable Securities" shall mean the shares of Common Stock from
time to time issued or issuable to the holders of the Convertible Note upon the
conversion thereof or hereafter acquired by Purchasers or which they hereafter
obtain the right to acquire pursuant to any dividend, distribution, stock split
or similar transaction or rights to the extent that all of the holders of the
Common Stock received shares of Common Stock.

          "Registration Statement" shall have the meaning ascribed to it in
Section 3.

          "Shelf Registration" shall have the meaning ascribed to it in
Section 2.

          "Shelf Registration Statement" shall have the meaning ascribed to it
in Section 2.

          2. Shelf Registration. As promptly as practicable, but in any event no
             ------------------
later than 90 days after the Closing Date, Company shall file with the SEC and
thereafter use its best efforts to cause to be declared effective on or prior to
the 120th day after the Closing Date a registration statement (the "Shelf
Registration Statement") on an appropriate form under the Securities Act
relating to the offer and sale of the Conversion Shares by the Holders thereof
from time to time in accordance with the methods and distribution set forth in
the Shelf Registration Statement and Rule 415 under the Securities Act
(hereafter, the "Shelf Registration"). Company shall use its best efforts to
keep the Shelf Registration Statement continuously effective in order to permit
the prospectus included therein to be lawfully delivered by Holders for a period
of 4 years from the date of issuance of the Conversion Shares upon the
conversion of the Note or such shorter period that will terminate when all the
Conversion Shares have been sold pursuant thereto; provided, however, that
                                                   --------  -------
Company shall be deemed not to have used its best efforts to keep the Shelf
Registration Statement effective during the requisite period if it voluntarily
takes any action that would result in the Holders covered thereby not being able
to sell the Conversion Shares during that period, unless such action is required
by applicable law. Notwithstanding any other provisions of this Agreement to the
contrary, Company shall cause the Shelf Registration Statement and the related
prospectus to be and any amendment or supplement thereto, as of the effective
date of the Shelf Registration Statement, amendment or supplement, (i) to comply
in all material respects with the applicable requirements of the Securities Act
and the rules and regulations of the SEC and (ii) not to contain any untrue
statement of material fact or omit to state a material fact required to be
stated therein or necessary in order to make the statements therein, in light of
the circumstances in which they were made, not misleading.

          3. Incidental Registration. If Company at any time proposes to file on
             ---------- ------------
its behalf a registration statement under the Securities Act on any form (other
than a

                                       2
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Registration Statement on Form S-4 or S-8 or any successor form for securities
to be offered in a transaction of the type referred to in Rule 145 under the
Securities Act or to employees of Company pursuant to any employee benefit plan,
respectively) for the general registration of securities (an "Incidental
Registration Statement", and together with the Shelf Registration Statement, a
"Registration Statement"), it will give written notice to all Holders at least
30 days before the initial filing with the SEC of such Registration Statement,
which notice shall set forth the intended method of disposition of the
securities proposed to be registered by Company.  The notice shall offer to
include in such filing the aggregate number of shares of Registrable Securities
as such Holders may request.

          Each Holder desiring to have Registrable Securities registered under
this Section 3 shall advise Company in writing within 10 Business Days after the
date of receipt of such offer from Company, setting forth the amount of such
Registrable Securities for which registration is requested.  Company shall
thereupon include in such filing the number of shares of Registrable Securities
for which registration is so requested, subject to the next sentence, and shall
use its best efforts to effect registration under the Securities Act of such
shares.  In connection with any registration subject to this Section 3, which is
to be effected in a firm commitment underwriting, Company will not be required
to include Registrable Securities in such underwriting unless the Holder of such
Registrable Securities accepts the terms and conditions of the underwriting
agreement which is agreed upon between Company and the managing underwriter
selected by Company, so long as such underwriting agreement conforms to industry
standards and practices and the obligations and liabilities imposed on the
Holders under such agreement are customary for the stockholders selling
securities in an underwritten offering.  If the managing underwriter of a
proposed public offering shall advise Company in writing that, in its opinion,
the distribution of the Registrable Securities requested to be included in the
registration concurrently with the securities being registered by Company would
materially and adversely affect the distribution of such securities by Company,
then all selling security holders shall reduce the amount of securities each
intended to distribute through such offering on a pro rata basis.  Except as
otherwise provided in Section 5, all expenses of such registration shall be
borne by Company.

          4. Registration Procedures. In connection with the requirements of
             ------------ ----------
Company pursuant to the provisions of Section 2 or if the Company is required by
the provisions of Section 3 to use its best efforts to effect the registration
of any of its securities under the Securities Act, Company will, as
expeditiously as possible:

               (a) in the case of any incidental registration pursuant to
Section 3, prepare and file with the SEC an Incidental Registration Statement
with respect to such securities and use its best efforts to cause such
Registration Statement to become and remain effective for a period of time
required for the disposition of such securities by the holders thereof, but not
to exceed 120 days (or, with respect to any underwritten offering, such shorter
period as the underwriters need to complete the distribution of the registered
offering);

                                       3
<PAGE>

               (b) prepare and file with the SEC such amendments and supplements
to such Registration Statement and the prospectus used in connection therewith
as may be necessary to keep such Registration Statement effective and to comply
with the provisions of the Securities Act with respect to the sale or other
disposition of all securities covered by such Registration Statement until, in
the case of an Incidental Registration Statement filed pursuant to Section 3,
the earlier of such time as all of such securities have been disposed of in a
public offering or the expiration of 120 days, or in the case of a Shelf
Registration Statement filed pursuant to Section 2, such time as is set forth in
Section 2;

               (c) furnish, to such selling security holders such number of
copies of a summary prospectus or other prospectus, including a preliminary
prospectus, in conformity with the requirements of the Securities Act, and such
other documents, as such selling security holders may reasonably request;

               (d) use its best efforts to register or qualify the securities
covered by such Registration Statement under such other securities or blue sky
laws of such jurisdictions within the United States and Puerto Rico as each
holder of such securities shall request (provided, however, that Company shall
                                         --------  -------
not be obligated to qualify as a foreign corporation to do business under the
laws of any jurisdiction in which it is not then qualified or to file any
general consent to service or process), and do such other reasonable acts and
things as may be required of it to enable such holder to consummate the
disposition in such jurisdiction of the securities covered by such Registration
Statement;

               (e) furnish, at the request of any Holder requesting registration
of Registrable Securities, on the date that such shares of Registrable
Securities are delivered to the underwriters for sale pursuant to such
registration or, if such Registrable Securities are not being sold through
underwriters, on the date that the Registration Statement with respect to such
shares of Registrable Securities becomes effective, (1) an opinion, dated such
date, of the independent counsel representing Company for the purposes of such
registration, addressed to the underwriters, if any, and if such Registrable
Securities are not being sold through underwriters, then to the Holders making
such request, in customary form and covering matters of the type customarily
covered in such legal opinions; and (2) a comfort letter dated such date, from
the independent certified public accountants of Company, addressed to the
underwriters, if any, and if such Registrable Securities are not being sold
through underwriters, then to the Holder making such request and, if such
accountants refuse to deliver such letter to such Holder, then to Company, in a
customary form and covering matters of the type customarily covered by such
comfort letters and as the underwriters or such Holder shall reasonably request.
Such opinion of counsel shall additionally cover such other legal matters with
respect to the registration in respect of which such opinion is being given as
such Holders may reasonably request. Such letter from the independent certified
public accountants shall additionally cover such other financial matters
(including information as to the period ending not more than five Business Days
prior to the date of such letter) with respect to

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<PAGE>

the registration in respect of which such letter is being given as the Holders
of a majority of the Registrable Securities being so registered may reasonably
request;

               (f) enter into customary agreements (including an underwriting
agreement in customary form) and take such other actions as are reasonably
required in order to expedite or facilitate the disposition of such Registrable
Securities;

               (g) otherwise use its best efforts to comply with all applicable
rules and regulations of the SEC, and make available to its security holders, as
soon as reasonably practicable, but not later than 18 months after the effective
date of the Registration Statement, an earnings statement covering the period of
at least 12 months beginning with the first full month after the effective date
of such Registration Statement, which earnings statement shall satisfy the
provisions of Section 11(a) of the Securities Act;

               (h) give written notice to Holders:

                    (i) when such Registration Statement or any amendment
thereto has been filed with the SEC and when such Registration Statement or any
posteffective amendment thereto has become effective;

                    (ii) of any request by the SEC for amendments or supplements
to such Registration Statement or the prospectus included therein or for
additional information;

                    (iii) of the issuance by the SEC of any stop order
suspending the effectiveness of such Registration Statement or the initiation of
any proceedings for that purpose;

                    (iv) of the receipt by Company or its legal counsel of any
notification with respect to the suspension of the qualification of the Common
Stock for sale in any jurisdiction or the initiation or threatening of any
proceeding for such purpose; and

                    (v) of the happening of any event that requires Company to
make changes in such Registration Statement or the prospectus in order to make
the statements therein not misleading (which notice shall be accompanied by an
instruction to suspend the use of the prospectus until the requisite changes
have been made);

               (i) use its best efforts to prevent the issuance or obtain the
withdrawal of any order suspending the effectiveness of such Registration
Statement at the earliest possible time;

               (j) furnish to each Holder, without charge, at least one copy of
such Registration Statement and any post-effective amendment thereto, including

                                       5
<PAGE>

financial statements and schedules, and, if the Holder so requests in writing,
all exhibits (including those, if any, incorporated by reference);

               (k) cooperate with the Holders to facilitate the timely
preparation and delivery of certificates representing the Conversion Shares to
be sold free of any restrictive legends and in such denominations and registered
in such names as the Holders may request a reasonable period of time prior to
sales of the Conversion Shares;

               (l) upon the occurrence of any event contemplated by Section
4(h)(v) above, promptly prepare a post-effective amendment to such Registration
Statement or a supplement to the related prospectus or file any other required
document so that, as thereafter delivered to Holders, the prospectus will not
contain an untrue statement of a material fact or omit to state any material
fact necessary to make the statements therein, in light of the circumstances
under which they were made, not misleading. If the Company notifies the Holders
in accordance with Section 4(h)(v) above to suspend the use of the prospectus
until the requisite changes to the prospectus have been made, then the Holders
shall suspend use of such prospectus, and the period of effectiveness of such
Registration Statement provided for above shall each be extended by the number
of days from and including the date of the giving of such notice to Holders
shall have received such amended or supplemented prospectus pursuant to this
Section 4(l);

               (m) (i) make reasonably available for inspection by the Holders,
any underwriter participating in any disposition pursuant to such Registration
Statement and any attorney, accountant or other agent retained by the Holders or
any such underwriter all relevant financial and other records, pertinent
corporate documents and properties of the Company and (ii) cause the Company's
officers, directors and employees to supply all relevant information reasonably
requested by the Holders or any such underwriter, attorney, accountant or agent
in connection with the registration; provided that the foregoing inspection and
                                     --------
information gathering shall be coordinated on behalf of the Purchaser by
Purchaser and on behalf of the other parties, by one counsel designated by and
on behalf of such other parties as described in Section 4; and

               (n) in connection with any underwritten offering, make
appropriate officers of Company available to the selling security holders for
meetings with prospective purchasers of the Registrable Securities and prepare
and present to potential investors customary "road show" material in a manner
consistent with other new issuances of securities similar to the Registrable
Securities, in connection with any proposed sale of the Registrable Securities
in an aggregate offering of at least $10 million.

          It shall be a condition precedent to the obligation of Company to take
any action pursuant to this Agreement in respect of the securities which are to
be registered at the request of any Holder that such Holder shall furnish to
Company such information regarding the securities held by such Holder and the
intended method of disposition

                                       6
<PAGE>

thereof as Company shall reasonably request and as shall be required in
connection with the action taken by Company.

          5. Expenses. All expenses incurred in complying with this Agreement,
             --------
including, without limitation, all registration and filing fees (including all
expenses incident to filing with the NASD), printing expenses, fees and
disbursements of counsel for Company, the reasonable fees and expenses of
counsel for the selling security holders (selected by those holding a majority
of the shares being registered), expenses of any special audits incident to or
required by any such registration and expenses of complying with the securities
or blue sky laws of any jurisdiction pursuant to Section 4(d), shall be paid by
Company, except that:

               (a) all such expenses in connection with any amendment or
supplement to a Registration Statement or prospectus required to be filed
pursuant to Section 3 which is filed more than 180 days after the effective date
of such Registration Statement because any Holder has not effected the
disposition of the securities requested to be registered shall be paid by such
Holder;

               (b) Company shall not be liable for any fees, discounts or
commissions to any underwriter or any fees or disbursements of counsel for any
underwriter in respect of the securities sold by such Holder; and

               (c) in the case of any underwritten offering pursuant to Section
2 hereof, Company shall be liable only for those fees of counsel for the Holders
to the extent that such fees do not exceed in the aggregate $100,000.

          6.  Indemnification and Contribution.
              --------------------------------
               (a) In the event of any registration of any Registrable
Securities under the Securities Act pursuant to this Agreement, Company shall
indemnify and hold harmless the holder of such Registrable Securities, such
holder's directors and officers, and each other person (including each
underwriter) who participated in the offering of such Registrable Securities and
each other person, if any, who controls such holder or such participating person
within the meaning of the Securities Act, against any losses, claims, damages or
liabilities, joint or several, to which such holder or any such director or
officer or participating person or controlling person may become subject under
the Securities Act or any other statute or at common law, insofar as such
losses, claims, damages or liabilities (or actions in respect thereof) arise out
of or are based upon (i) any alleged untrue statement of any material fact
contained, on the effective date thereof, in any Registration Statement under
which such securities were registered under the Securities Act, any preliminary
prospectus or final prospectus contained therein, or any amendment or supplement
thereto, or (ii) any alleged omission to state therein a material fact required
to be stated therein or necessary to make the statements therein not misleading,
and shall reimburse such holder or such director, officer or participating
person or controlling person for any legal or any other expenses reasonably
incurred by such holder or such director, officer or participating person or
controlling person in

                                       7
<PAGE>

connection with investigating or defending any such loss, claim, damage,
liability or action; provided, however, that Company shall not be liable in any
                     --------  -------
such case to the extent that any such loss, claim, damage or liability arises
out of or is based upon any actual or alleged untrue statement or actual or
alleged omission made in such Registration Statement, preliminary prospectus,
prospectus or amendment or supplement in reliance upon and in conformity with
written information furnished to Company by such holder specifically for use
therein or (in the case of any underwritten offering) so furnished for such
purposes by any underwriter. Such indemnity shall remain in full force and
effect regardless of any investigation made by or on behalf of such holder or
such director, officer or participating person or controlling person, and shall
survive the transfer of such securities by such holder.

               (b) Each Holder, by acceptance hereof, agrees to indemnify and
hold harmless Company, its directors and officers and each other person, if any,
who controls Company within the meaning of the Securities Act against any
losses, claims, damages or liabilities, joint or several, to which Company or
any such director or officer or any such person may become subject under the
Securities Act or any other statute or at common law, insofar as such losses,
claims, damages or liabilities (or actions in respect thereof) arise out of or
are based upon information in writing provided to Company by such Holder
specifically for use in the following documents and contained, on the effective
date thereof, in any Registration Statement under which securities were
registered under the Securities Act at the request of such holder, any
preliminary prospectus or final prospectus contained therein, or any amendment
or supplement thereto. Notwithstanding the provisions of this paragraph (b) or
paragraph (c) below, no Holder shall be required to indemnify any person
pursuant to this Section 6 or to contribute pursuant to paragraph (c) below in
an amount in excess of the amount of the aggregate net proceeds received by such
Holder in connection with any such registration under the Securities Act.


               (c) If the indemnification provided for in this Section 6 from
the indemnifying party is unavailable to an indemnified party hereunder in
respect of any losses, claims, damages, liabilities or expenses referred to
therein, then the indemnifying party, in lieu of indemnifying such indemnified
party, shall contribute to the amount paid or payable by such indemnified party
as a result of such losses, claims, damages, liabilities or expenses in such
proportion as is appropriate to reflect the relative fault of the indemnifying
party and indemnified parties in connection with the actions which resulted in
such losses, claims, damages, liabilities or expenses, as well as any other
relevant equitable considerations. The relative fault of such indemnifying party
and indemnified parties shall be determined by reference to, among other things,
whether any action in question, including any untrue or alleged untrue statement
of a material fact or omission or alleged omission to state a material fact, has
been made by, or relates to information supplied by, such indemnifying party or
indemnified parties, and the parties' relative intent, knowledge, access to
information and opportunity to correct or prevent such action. The amount paid
or payable by a party as a result of the losses, claims, damages, liabilities
and expenses referred to above shall be deemed to include any legal

                                       8
<PAGE>

or other fees or expenses reasonably incurred by such party in connection with
any investigation or proceeding.

          The parties hereto agree that it would not be just and equitable if
contribution pursuant to this Section 6(c) were determined by pro rata
allocation or by any other method of allocation which does not take account of
the equitable considerations referred to in the immediately preceding paragraph.
No Person guilty of fraudulent misrepresentation (within the meaning of Section
11(f) of the Securities Act) shall be entitled to contribution from any Person
who was not guilty of such fraudulent misrepresentation.

          7. Certain Limitations on Registration Rights. Notwithstanding the
             ------- ----------- -- ------------ ------
other provisions of this Agreement:

               (a) Company shall not be obligated to register the Registrable
Securities of any Holder if, in the opinion of counsel to Company reasonably
satisfactory to the Holder and its counsel (or, if the Holder has engaged an
investment banking firm, to such investment banking firm and its counsel), the
sale or other disposition of such Holder's Registrable Securities, in the manner
proposed by such Holder (or by such investment banking firm), may be effected
without registering such Registrable Securities under the Securities Act;

               (b) Company shall have the right to delay the filing or
effectiveness of, or by written notice require the Holders to cease sales of
Registrable Securities pursuant to, a Shelf Registration Statement required
pursuant to Section 2 hereof during one or more periods aggregating not more
than 60 days in any twelve-month period (such period or periods, the "Suspension
Period") in the event that (i) Company would, in accordance with the advice of
its counsel, be required to disclose in the prospectus information not otherwise
then required by law to be publicly disclosed, (ii) in the judgment of Company's
Board of Directors, there is a reasonable likelihood that such disclosure, or
any other action to be taken in connection with the prospectus, would materially
and adversely affect any existing or prospective material business situation,
transaction or negotiation or otherwise materially and adversely affect Company,
or (iii) the Shelf Registration Statement can no longer be used under the
Securities Act; provided that the period of effectiveness of the Shelf
Registration Statement pursuant to Section 2 shall be extended by the length of
any such Suspension Period;

               (c) Notwithstanding Section 7(b) hereof, Company agrees that it
shall not impose a Suspension Period during the 30-day period following the date
on which the Shelf Registration is first declared effective by the SEC (the
"30-day Period") as a result of any activity initiated by Company, or in
response to any proposal, unless Company's Board of Directors determines in good
faith that it is required to impose a Suspension Period by law during such
30-day Period. To the extent Company imposes a Suspension Period during such
30-day Period as a result of such determination by Company's Board of Directors,
Company shall not, for such additional number of

                                       9
<PAGE>

consecutive days following the termination of such Suspension Period, impose an
additional Suspension Period, so as to provide the Holders with a total of 30
days without a Suspension Period; and

               (d) If Company suspends the Shelf Registration Statement or
requires the Holders to cease sales of the Common Stock pursuant to paragraph
(b) above, Company shall, as promptly as practicable following the termination
of the circumstances which entitled Company to do so, take such action as may be
necessary to reinstate the effectiveness of the Shelf Registration Statement
and/or give written notice to all Holders authorizing them to resume sales
pursuant to the Shelf Registration Statement. If, as a result thereof, the
prospectus included in the Shelf Registration Statement has been amended to
comply with the requirements of the Securities Act, Company shall enclose such
revised prospectus with a notice to Holders given pursuant to this paragraph
(d), and the Shareholders shall make no offers or sales of shares pursuant to
such Registration Statement other than by means of such revised prospectus.

          8. Selection of Managing Underwriters. The managing underwriter or
             --------- -- -------- ------------
underwriters for any offering of Registrable Securities to be registered
pursuant to Section 2 shall be of recognized national standing selected by the
holders of a majority of the shares being so registered, and shall be reasonably
acceptable to Company.

          9. Restrictions on Sale After Public Offering. Except for transfers
             ------------ -- ---- ----- ------ --------
made in transactions exempt from the registration requirements under the
Securities Act (other than Rule 144 thereunder), Company and each Holder hereby
agree not to offer, sell, contract to sell or otherwise dispose of any of their
Registrable Securities within 120 days after the date of any final prospectus
relating to the public offering of Common Stock, if underwritten, whether by
Company or by any Holders, except pursuant to such prospectus or with the
written consent of the managing underwriter or underwriters for such offering.

          10.  Miscellaneous.
               -------------

               (a) No Inconsistent Agreements. Company will not hereafter enter
                   -- ------------ ----------
into any agreement with respect to its securities which is inconsistent with the
rights granted to the Holders in this Agreement. Company has not previously
entered into any agreement with respect to any of its securities granting any
registration rights to any person.

               (b) Remedies. Each Holder, in addition to being entitled to
                   --------
exercise all rights granted by law, including recovery of damages, will be
entitled to specific performance of its rights under this Agreement. Company
agrees that monetary damages would not be adequate compensation for any loss
incurred by reason of a breach by it of the provisions of this Agreement and
hereby agrees to waive the defense in any action for specific performance that a
remedy at law would be adequate. In any action or proceeding brought to enforce
any provision of this Agreement or where any provision

                                       10
<PAGE>

hereof is validly asserted as a defense, the successful party shall be entitled
to recover reasonable attorneys' fees in addition to any other available remedy.

               (c) Amendments and Waivers. Except as otherwise provided herein,
                   ----------------------
the provisions of this Agreement may not be amended, modified or supplemented,
and waivers or consents to departure from the provisions hereof may not be given
unless Company has obtained the written consent of the Majority Holders.

               (d) Notice Generally. Any notice, demand, request, consent,
                   ----------------
approval, declaration, delivery or other communication hereunder to be made
pursuant to the provisions of this Agreement shall be sufficiently given or made
if in writing and either delivered in person with receipt acknowledged or sent
by registered or certified mail, return receipt requested, postage prepaid, or
by telecopy and confirmed by telecopy answerback, addressed as follows:

               (i) If to any Holder, at its last known address appearing on the
books of Company maintained for such purpose.

               (ii) If to Company, at

               Mastech Corporation
               1604 McKee Road
               Oakdale, Pennsylvania 15071
               Attention:  Jeffrey McCandless
               Telecopy Number:  (412) 787-9225

               with a copy to

               Buchanan Ingersoll
               One Oxford Centre
               301 Grant Street, 20th Floor
               Pittsburgh, Pennsylvania 15219
               Attention: Carl Cohen, Esq. and James Barnes, Esq.
               Telecopy Number: (412) 562-1041

or at such other address as may be substituted by notice given as herein
provided.  The giving of any notice required hereunder may be waived in writing
by the party entitled to receive such notice.  Every notice, demand, request,
consent, approval, declaration, delivery or other communication hereunder shall
be deemed to have been duly given or served on the date on which personally
delivered, with receipt acknowledged, telecopied and confirmed by telecopy
answerback or three Business Days after the same shall have been deposited in
the United States mail.

               (e) Successors and Assigns. This Agreement shall inure to the
                   ----------------------
benefit of and be binding upon the successors and assigns of each of the parties
hereto including any person to whom Registrable Securities are transferred.

                                       11
<PAGE>

               (f) Headings. The headings in this Agreement are for convenience
                   --------
of reference only and shall not limit or otherwise affect the meaning hereof.

               (g) Governing Law; Jurisdiction. This Agreement shall be governed
                   ---------------------------
by, construed and enforced in accordance with the laws of the State of New York
without giving effect to the conflict of laws provisions thereof. Each of the
parties hereby submits to personal jurisdiction and waives any objection as to
venue in the County of New York, State of New York. Service of process on the
parties in any action arising out of or relating to this Agreement shall be
effective if mailed to the parties in accordance with Section 10(d) hereof. The
parties hereto waive all right to trial by jury in any action or proceeding to
enforce or defend any rights hereunder.

               (h) Severability. Wherever possible, each provision of this
                   ------------
Agreement shall be interpreted in such manner as to be effective and valid under
applicable law, but if any provision of this Agreement shall be prohibited by or
invalid under applicable law, such provision shall be ineffective to the extent
of such prohibition or invalidity, without invalidating the remainder of such
provision or the remaining provisions of this Agreement.

               (i) Entire Agreement. This Agreement, together with the Purchase
                   ----------------
Agreement, represents the complete agreement and understanding of the parties
hereto in respect of the subject matter contained herein and therein. This
Agreement supersedes all prior agreements and understandings between the parties
with respect to the subject matter hereof.

                                       12
<PAGE>

          IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the date first above written.

                         MASTECH CORPORATION

                         By:_________________________________
                            Name:
                            Title:

                         GE CAPITAL EQUITY INVESTMENTS, INC.

                         By:_________________________________
                            Name:
                            Title:

                                       13