Sri Lanka Cricket said in a media release on Wednesday Dilshan would hold a news conference on Thursday to officially announce his retirement.
"I have decided to take this decision to allow Sri Lanka cricket to groom another youngster in my place," said Dilshan.
"I was to announce my retirement after the ZimbabweTtest series but unfortunately the tour was postponed."
Sri Lanka were to play two Tests on their tour of Zimbabwe from October.
The aggressive opener made his test debut in 1999 against Zimbabwe at Bulawayo and appeared in 87 Tests. In an international career spanning 14 years Dilshan scored 5,492 runs at an average of 40.98.
His 16 test centuries included a career best 193 against England at Lord's in 2011 as captain.
The 36-year-old will continue to play in the shorter 50 overs and Twenty20 formats for his country.
"I will discuss my future with the national selectors and if they need me I will play till the 2015 World Cup," he said.
- Sports & Recreation