Veteran trade unionist and senior Congress leader Kadavoor Sivadasan passed away at a private hospital in Thiruvananthapuram early on Friday morning, party sources said.
He was 87 and was under treatment for pneumonia.
A four-time legislator, Sivadasan was a minister in the Cabinets of K. Karunakaran and A.K Antony.
Starting his political career as a trade union leader from his home district Kollam, Sivadasan was elected MLA on a Revolutionary Socialist Party ticket in 1980 and 1982.
He later switched to the Congress, on whose ticket he won the 1991 and 2001 Assembly polls.