Kamal Basu, wife of former West Bengal chief minister Jyoti Basu, died at a Salt Lake nursing home on Tuesday night after protracted illness, doctors said in Kolkata.
She was 73 and is survived by her husband and son Chandan.
She had been suffering from diabetes, hypertension and renal problems and was admitted to the clinic on September 11 in a critical condition with complaints of respiratory distress and other complications, doctors said.
The body would be taken to the Keoratala crematorium from her son's residence at Indira Bhavan.
Communist Party of India-Marxist sources said Kamal Basu was an ardent supporter of the party. Party leaders, including state party secretary Anil Biswas, Left Front chairman Biman Bose, Commerce and Industry Minister Nirupam Sen and Health Minister Suryakanta Mishra, went to her residence to pay homage.