Soundaram Kailasam, mother-in-law of Union Home Minister P Chidamaram, died after a prolonged illness in Chennai this morning.
She was 87 and is survived by a son and three daughters, including Nalini Chidambaram, an advocate and wife of P Chidambaram.
A prolific Tamil scholar, Soundaram had authored many books and was a powerful orator.
Her husband, Justice P S Kailasam, a retired judge of the Supreme Court, predeceased her.
Tamil Nadu Chief Minister M Karunanidhi and his son, Deputy Chief Minister M K Stalin, condoled her death and placed a wreath on the body.
Soundaram's funeral would be held this evening, family sources said.