Director/PDMR Shareholding

GlaxoSmithKline PLC
06 May 2008



         Notification of Transactions of Directors, Persons Discharging
                 Managerial Responsibility or Connected Persons

The Administrators of the GlaxoSmithKline Performance Share Plan notified the
Company and the under-mentioned persons on 6 May 2008 of an increase in their
notional interests in Ordinary shares at a price of £11.20 per share and
Ordinary Share ADRs at a price of $44.11 per ADR following the notional
re-investment of the dividend to be paid to shareholders on 10 July 2008.




                                      Ordinary shares                    ADRs
Dr JP Garnier                                                        5,730.80
Mr A P Witty                                 4,604.87
Mr J S Heslop                                3,742.11
Dr M M Slaoui                                  332.90                1,657.54
Mrs C E Bruck Slaoui                            26.53                   37.72
Mr C Viehbacher                                                      1,508.67
Mr J M Clarke                                2,790.11
Mr M Dunoyer                                 1,050.82
Mr E J Gray                                    870.97
Dr R G Greig                                                           917.26
Mr D Learmouth                                 573.76
Mr W C Louv                                                            666.68
Mr D J Phelan                                                        1,412.58
Dr D Pulman                                                            917.26
Mr S M Werner                                                          191.52

The notional dividends accrued will be paid out in proportion to the percentage
of participants' Performance Share Plan holdings that vest following the end of
the relevant three year measurement period.

This notification relates to transactions notified in accordance with Disclosure
and Transparency Rules 3.1.4R(1)(a).

S M Bicknell
Company Secretary

6 May 2008


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