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Via Facsimile and U.S. Mail Mail Stop 6010                                                                                                   June 26, 2008  Mr. Julian Heslop Chief Financial Officer GlaxoSmithKline plc  980 Great West Road Brentford, Middlesex TW8 9GS England
Re: GlaxoSmithKline plc  Form 20-F for Fiscal Year Ended December 31, 2007
File No. 1-15170

Dear Mr. Heslop:

We have reviewed your filing and have the following comments.  We have
limited our review to only your financial stat ements and related disclosures and do not
intend to expand our review to  other portions of your documents.  In our comments, we
ask you to provide us with information to better understand your disclosure.  Where a
comment requests you to revise disclosure, the information you provide should show us
what the revised disclosure will look like a nd identify the annual or quarterly filing, as
applicable, in which you intend to first incl ude it.  If you do not believe that revised
disclosure is necessary, e xplain the reason in your res ponse.  After reviewing the
information provided, we may raise additional comments and/or request that you amend your filing.   Please understand that the purpose of our re view process is to assist you in your
compliance with the applicable disclosure  requirements and to  enhance the overall
disclosure in your filing.  We look forward to  working with you in these respects.  We
welcome any questions you may have about our comments or on any other aspect of our review.  Feel free to call us at the telephone numbers listed at the end of this letter.

Form 20-F for the year ended December 31, 2007

Financial Statements

Consolidated Income Statement, page 90

1. You disclosed “Business Performance”, a non-IFRS measure, prominently on the
face of your income statement and throughout your annual report in 2007.

Mr. Julian Heslop
GlaxoSmithKline plc
June 26, 2008 Page 2
Measures that are prohibited by Item 10(e)  of Regulation S-K should not be added
to the face of the primary financial statements unless expressly permitted under the GAAP used in the company's primar y financial statements.  We understand
that paragraph 33 of the Financial Reporting Review Panel Preliminary Report on
IFRS Implementation stated that non-IF RS measures should not be given undue
prominence.  Please tell us whether non-IFRS measures are expressly permitted under IFRS as adopted by the EU and as published by the IASB and cite for us the relevant authoritative literature.

If the non-IFRS measures are not expre ssly permitted please clarify to us how you
meet the guidance in the note to paragraph (e) of Item 10(e) of Regulation S-K regarding the use of non-GAAP financial meas ures for a foreign private issuer or
provide the disclosures required by Item 10 (e) of Regulation S-K.  In addition,
please clarify in the filing what cost s are excluded from Business performance
and why you believe it is appr opriate to exclude them.
 Statements of Cash Flows, page 92

2. As previously requested in our lette r dated January 18, 2007 and confirmed by
your letter dated January 31, 2007, please revise your Statements of Cash Flows to begin with profit after taxation.  We do not believe it is appropriate to begin
your Cash Flow Statement with Cash generated from operations.

Note 2 – Accounting Policies

Research and Development, page 95

3. You disclosed that development expenditure  is capitalized when the criteria for
recognizing an asset are met, usually when a regulatory filing has been made in a major market and approval is consid ered highly probable.  Based on the
significance of your research and deve lopment function, please disclose the
following:

• The types of regulatory filings that  trigger the capita lization of product
development expenditures;
• The circumstances under which you capit alize development costs other than
when a regulatory filing has been made  and approval is considered highly
probable; and
• The annual amount of product developm ent expenditures that have been
capitalized.

Mr. Julian Heslop
GlaxoSmithKline plc
June 26, 2008 Page 3  Note 28 – Pensions and Other pos t-Employment Benefits, page 117

4. You disclosed that contribu tions to defined benefit schemes are determined in
accordance with the advice of independent, professionally qualified actuaries.
You also disclosed that pension costs of  defined benefit schemes for accounting
purposes have been assessed in accordan ce with independent actuarial advice,
using the projected unit method and that pe nsion liabilities ar e generally assessed
annually in accordance with th e advice of independent actuaries.  Please tell us
the intent of this reference to an actuar y. While you are not required to indicate or
infer that the actuaries determine your pe nsion costs, when you do, you must also
disclose their names. If you include th eir names in or incorporate them by
reference into a 1933 Securi ties Act filing, you will also  need to include the
consents of the independent actuaries.

*    *    *    *
  Please provide us the information request ed within 10 business days of the date
of this letter or tell us when you will provide a respons e prior to the expiration of the 10-
day period.  Please furnish a letter with your responses that keys your responses to our
comments.  Detailed letters gr eatly facilitate our review.  You should furnish the letter on
EDGAR under the form type label CORRESP.

 We urge all persons who are responsible for the accuracy and adequacy of the
disclosure in the filing to be certain that the filing include all in formation required under
the Securities Exchange Act of 1934 and th at they have provided all information
investors require for an informed invest ment decision.  Since the company and its
management are in possession of all facts re lating to a company’s disclosure, they are
responsible for the accuracy and adequacy of the disclosures they have made.

 In connection with responding to our co mments, please provide, in your letter, a
statement from the company acknowledging that:
• the company is responsible for the adequacy  and accuracy of the disclosure in the
filings;
• staff comments or changes to disclosure  in response to staff comments do not
foreclose the Commission from taking any action with respect to the filing; and
• the company may not assert staff comme nts as a defense in any proceeding
initiated by the Commission or any person under the federal secu rities laws of the
United States.

In addition, please be advise d that the Division of Enfo rcement has access to all
information you provide to the staff of the Divi sion of Corporation Fi nance in our review
of your filing or in response to our comments on your filing.

Mr. Julian Heslop
GlaxoSmithKline plc June 26, 2008 Page 4
 You may contact Gus Rodriguez, Sta ff Accountant at ( 202) 551-3752, or Mary
Mast, Senior Accountant, at (202) 551-3613  if you have questions regarding these
comments. In this regard, do not hesi tate to contact me, at (202) 551-3679.

Sincerely,    Jim B. Rosenberg Senior Assistant Chief Accountant