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Via Facsimile and U.S. Mail Mail Stop 6010                                                                                                   August 13, 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 July 30, 2008 response to our June 26, 2008 letter and
have the following additional comments.  In  our comments, we ask you to provide us
with information to better understand your di sclosure.  Where a comment requests you to
revise disclosure, the information you provide should show us what the revised disclosure
will look like and identify the annual or quart erly filing, as applicable, in which you
intend to first include it.  If you do not believe that revi sed disclosure is necessary,
explain the reason in your res ponse.  After reviewing the information provided, we may
raise additional comments and/or request that you amend your filing.

Financial Statements

Consolidated Income Statement, page 90

1. We acknowledge your response to prior comment 1. Although you now intend to omit the description of “business perfo rmance” as a “non-IFRS measure” from
your future filings, your filing will continue  to include this measure.  Since this
measure excludes restructuring expenses and significant acquisitions, it is a non-
GAAP measure that is still subject to Item  10 of Regulation S-K.  Please address
the following for us:
• Please cite for us relevant authoritative literature that expressly permit the
disclosure of “non-IFSR measures” sin ce paragraph 83 of IAS 1 only refers to
the addition of line items, headings and totals as opposed to complete columns
of “non-IFRS measures.”
• Please address the question raised in  our prior comment as to whether
paragraph 33 of the Financial Reporti ng Review Panel Preliminary Report on

Mr. Julian Heslop
GlaxoSmithKline plc
August 13, 2008 Page 2
IFRS Implementation permits the undue  prominence of “non-IFRS measures”
on your income statement.
• Please clarify in the filing what revenues and costs are excluded from
“business performance.”
• You disclosed that you believe that “business performance” gives a more
useful indication of underlying performan ce.  However, it is unclear how this
measure is a useful indicator of performance to an investor since you make
frequent acquisitions and it appears that the restru cturing charges that are
excluded are recurring operating expe nses.  Please provide enhanced
disclosures of why it is m eaningful to investors to exclude these revenues and
costs from “business performance” and why the “business performance” measure provides useful information to an investor of your financial condition
and results of operations.
• Please provide the disclosures required by Item 10(e) of Regulation S-K given
that Form 20-F filers are required to  comply with the requirements of
Regulation S-K or tell us how you ha ve complied with this regulation.

Statements of Cash Flows, page 92

2. We acknowledgement your response to comment 2, but continue to believe as previously requested in our letter date d January 18, 2007 and confirmed by your
letter dated January 31, 2007, that you s hould 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.  In
addition, the two beginning line items on your  Cash Flow Statement do not agree
with any line items on your Statements of Operations.

*    *    *    *
 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.

Mr. Julian Heslop
GlaxoSmithKline plc August 13, 2008 Page 3
  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