Tesco's director of group IT Philip Clarke is taking over as chief executive after Sir Terry Leahy decided to step down after 14 years.
Leahy is retiring at the age of 55 and will be replaced by Clarke in March 2011. Clarke currently has responsibility for the group's international operations in Asia and Europe as well as group IT.
Clarke joined the board 12 years ago with responsibility for the supply chain. IT was added to his remit a year later.
In January 2004 he took over international operations while retaining IT, and is now responsible for almost 2,000 stores.
Tesco said in a statement, "He has been at the heart of all our new moves and operational improvements across Asia and Europe in recent years, including China, India and Turkey, building teams and developing talent in these important markets."
Leahy added, "I am delighted Phil Clarke has accepted the role of CEO. I have worked with Phil at Tesco for many years and I am confident he has all the necessary talent, energy and experience to take the group forward. He will be supported by an outstanding team of senior executives who together represent one of the strongest leadership teams in the world of retailing."