He was 86 and survived by his wife and two sons.
Rath who was ailing had been admitted to the ICU of the SCB Medical College Hospital last week where he passed this morning, family sources said.
Born in Jagatsinghpur district in 1922, Rath started his career as a journalist and later practiced law in the Orissa High Court.
In 1959 he was appointed standing counsel and became government advocate in the high court in 1963.
He served as advocate general of the state from 1972 to 77 and again from 1982 to 1990.
Chief Justice of Orissa High Court A K Ganguly, judges, Higher Education minister Samir Dey and a host of dignitaries visited Rath's residence to paid their last tributes.
Chief Minister Naveen Patnaik condoled Rath's demise saying that it was an irreparable loss to the state.
Rath was also the founder of the prestigious 'Sahitya Bharati Samman' for Oriya litterateurs.