GlaxoSmithKline said today Mr Richard Sykes, the man who oversaw its expansion into the world's second largest drugs company, will step down as chairman at its annual general meeting on May 20th.
Non-executive director Christopher Hogg will succeed him, the company said in a statement.
"Having overseen the successful merger of GlaxoSmithKline and as I approach my 60th birthday in August, I feel now is the right time to depart."
A spokesman told Reutersthat Mr Sykes' departure would not lead to any change in strategy at Europe's biggest pharmaceuticals company. "The executive team is the same as it was on Friday," he said.
Mr Sykes, who joined Glaxo Research Limited in 1972, led the company's acquisition of rival healthcare firm Wellcome in 1995, and was appointed chairman of the combined business in May 1997.
He was then the principal architect of Glaxo Wellcome's merger with SmithKline Beecham at the end of 2000.