“I have achieved what I wanted to achieve. There is nothing left or any target to reach,” the 38-year-old said.
Muralitharan will quit Test cricket after the first Test against India starting in Galle on July 18, but may be available for next year’s limited-overs World Cup.
The off-spinner, affectionately known as Murali, is the most successful bowler in history with record hauls in both Test (792) and one-day (515) cricket.
The island’s cricket governing body said Muralitharan had the blessing of President Mahinda Rajapakse to retire early, although the bowler had previously said he wanted to continue until the home series against the West Indies in November.
“I was thinking about it for a long time and wanted to retire after playing the West Indies,” Muralitharan said.
“However, I did not want to keep so many talented youngsters waiting. I changed my decision and thought why not retire against India since they are the number one Test side.”
Muralitharan said he had no regrets about quitting because he had reached the bowler’s peak in both forms of the game.
“I’m very happy because I have played Test cricket for so long,” he said. “The decision to retire was not difficult. I am not getting any younger. You can’t play for ever and ever.”
Reports said Muralitharan preferred not to wait until the end of the three Test matches against India because he was unsure of being able to manage the workload of an entire series.
He begins the Galle Test, the 133rd of his career, needing eight wickets to reach the 800-wicket target.
Sri Lanka’s former World Cup winning captain Arjuna Ranatunga, who mentored Muralitharan in his younger days, said the off-spinner’s time was up.
“I feel he made the decision at the right time,” Ranatunga said in Colombo. “He has been struggling over the past few months with nagging injuries.
“I am glad he is going now. Better go when the public ask why, rather than why not. Its a very sad day for Sri Lanka because he has been a top class servant of the country.”
Muralitharan’s 18-year career was marred by controversy due to his bent-arm action — the result of an elbow deformity since birth — which helped him impart considerable turn and bounce even on the most placid wickets.
But the International Cricket Council, which carried out bio-mechanical tests on the bowler, cleared him of a suspect action.
Muralitharan will continue to make himself available for one-day matches and hopes to play in the 2011 World Cup if needed, his manager Kushil Gunasekara said.
“He wanted to retire from all forms of international cricket after the Galle Test, but the cricket board wanted him to stay on till the World Cup next year,” Gunasekara said.
The premier limited-overs tournament will be hosted by India, Sri Lanka and Bangladesh in February-April next year.