BP chairman Carl-Henric Svanberg said: "The BP board is deeply saddened to lose a CEO whose success over some three years in driving the performance of the company was so widely and deservedly admired.
"The tragedy of the Macondo well explosion and subsequent environmental damage has been a watershed incident. BP remains a strong business with fine assets, excellent people and a vital role to play in meeting the world's energy needs. But it will be a different company going forward, requiring fresh leadership supported by robust governance and a very engaged board.
"We are highly fortunate to have a successor of the calibre of Bob Dudley who has spent his working life in the oil industry both in the US and overseas and has proved himself a robust operator in the toughest circumstances," Svanberg said.