Director/PDMR Shareholding

GlaxoSmithKline PLC
21 February 2008

                  Notification of Transactions of Directors and
                  Persons Discharging Managerial Responsibility

      Vesting of awards made under GlaxoSmithKline's share plans in 2004


This notification, prepared in accordance with Disclosure and Transparency Rule
3.1.4R(1)(a), sets out the vesting of share awards made in 2004, under the
GlaxoSmithKline Performance Share Plan.

Performance Share Plan

The three-year performance period for the GlaxoSmithKline Performance Share Plan
(PSP) awards made in 2004, which commenced on 1 January 2005, came to an end on
31 December 2007.

The Remuneration Committee of the Board of GlaxoSmithKline plc (GSK) considered
the performance achieved in respect of the PSP awards and determined that the
PSP awards granted in 2004 vested as set out in the table below. The vesting of
these awards was subject to the Company's relative Total Shareholder Return
(TSR) performance for the individuals who were Executive Directors or Corporate
Executive Team (CET) members at the time the awards were made. For other
participants, the vesting of the awards was subject in part to TSR and in part
to the Company's Earnings per Share (EPS) growth over the performance period.

The following Executive Directors and CET members, who are all Persons
Discharging Managerial Responsibility (PDMRs), have received the following final
awards in respect of the awards made in 2004. The unvested balance of each award
has lapsed.

                                         Number of Shares/ADSs vesting

                                       Shares                      ADSs
Dr JP Garnier*                                                     86,327
Mr A P Witty*                          33,272
Mr R M Bondy                           33,272
Mr J M Clarke                          20,687
Mr M Dunoyer                           12,531
Mr E J Gray                             9,177
Mr J S Heslop*                          6,698
Mr D Learmouth                          4,332
Dr M Slaoui*                            9,177
Dr R G Greig**                                                     10,791
Mr W C Louv                                                         4,056
Mr D J Phelan                                                      16,618
Mr D Pulman                                                        10,791
Mr D M Stout                                                       31,941
Mr C Viehbacher*                                                   16,618

* denotes an Executive Director

** deferred until retirement




Share Option Plan

The three-year performance period for the GlaxoSmithKline Share Option Plan
(SOP) awards made to appointed CET members in 2004, at an option price of £11.23
(or US$43.730 in the case of ADSs), which commenced on 1 January 2005, came to
an end on 31 December 2007. The performance conditions for this grant were met.
The Remuneration Committee of the Board of GSK therefore confirmed that they
were exercisable in full.

                                         Number of Shares/ADSs exercisable

                                       Shares                      ADSs
Dr JP Garnier*                                                     460,000
Mr A P Witty*                          177,500
Mr R M Bondy                           177,500
Mr M Dunoyer                            70,000
Mr J S Heslop*                          62,250
Dr R G Greig                                                        57,500
Mr D J Phelan                                                       88,750
Mr D Pulman                                                         57,500
Mr D M Stout                                                       170,000
Mr C Viehbacher*                                                    88,750

* denotes an Executive Director



The Company, Directors, and Persons Discharging Managerial Responsibility were
advised of these transactions on 21 February 2008.



S M Bicknell
Company Secretary



21 February 2008


Enquiries:

UK Media enquiries:                        Philip Thomson        [phone]
                                           Alice Hunt            [phone]
                                           Gwenan White          [phone]

US Media enquiries:                        Nancy Pekarek         [phone]
                                           Mary Anne Rhyne       [phone]

European Analyst/Investor enquiries:       David Mawdsley        [phone]
                                           Sally Ferguson        [phone]
                                           Gary Davies           [phone]

US Analyst/ Investor enquiries:            Frank Murdolo         [phone]
                                           Tom Curry             [phone]




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