Gopu (82) was suffering from blood cancer and was undergoing treatment at a private hospital here, party sources said.
He is survived by a daughter.
As per his wishes, his body would be handed over to the Government Hospital for research.
Born in Thanjavur district in the state, he participated in India's freedom struggle and had underwent prison terms, CPI state unit secretary D Pandian said in a statement.
He had gone underground when the party was banned in 1948.
He said Gopu, who was an active trade union leader, had served as National Council member for more than 30 years.
DMK chief M Karunanidhi expressed grief over the death of Gopu, saying he was shocked to learn about the demise of the communist veteran.
Gopu had strived for the welfare of the poor, especially the labour class, he said while expressing his condolences to the bereaved family.
