Ranatunga, 40, was elected to Parliament from the district of Colombo after contesting under President Chandrika Kumaratunga's leftist Freedom Alliance which won 105 seats in a hung Parliament.
He first entered Parliament in December 2001, a year after retiring from international cricket, saying he felt he owed "something to the nation" and wanted to improve not only cricket and athletics, but other sports as well.
Ranatunga became a hero in Sri Lanka after leading his team to victory in the 1996 cricket World Cup.
He captained Sri Lanka in 193 One-day matches, winning 89 and losing 95. Eight ended in no result and one was a tie.
He played a total of 91 Test matches and was captain for 56, during which he secured 12 wins, 19 losses and 25 draws.