Sangakkara said he's immediately stepping down as skipper of the national one-day and Twenty20 teams but wants to continue to be the test captain for the tour of England from May-July, and possibly the home series against Australia, to ensure a smooth transition.
The wicketkeeper-batsman wanted to keep playing international cricket, saying he was available for selection in all forms of the game.
He said he made up his mind before Sri Lanka reached its second straight World Cup final.
"It is in the best long-term interests of the team that I step down now as national captain so that a new leader can be properly groomed for the 2015 World Cup in Australia," Sangakkara said in a statement.
"I will be 37 by the next World Cup and I cannot therefore be sure of my place in the team.
"It is better that Sri Lanka is led now by a player who will be at the peak of their career during that tournament."
Later, he urged Sri Lanka cricket to begin planning now for the next four years.
"This is the time that we have to plan for the future, and the future starts now, not in another six months time, not in another year," Sangakkara said.
"Myself, Mahela (Jayawardene), we are, maybe, remnants of a past era. New blood has come in and a lot of younger players have stood up and have been counted. So I think now it's their time, it's their future. And they need to make sure that they carry this team forward."
Sangakkara has captained Sri Lanka in 45 one-day internationals, winning 27, and losing 14. Also he has won 12 Twenty20s, losing nine.
He has 8244 runs from 94 tests at an average of over 57; 9164 runs in 291 ODIs; and 777 runs in 29 Twenty20s.
The International Cricket Council named him captain of a paper World Cup XI after the tournament.
