"De Souza was shifted here from another private hospital last night. He was breathless. He died of heart attack this morning at 9.15 AM," said Dr Shekhar Salkar, clinical head at Manipal Hospital near here.
He is survived by wife Grace and two daughters Joanne and Suzie.
A surgeon-turned-politician, De Souza twice served as the state's Chief Minister from Congress. He represented Goa Rajiv Congress (a breakaway faction of Indian National Congress) during his third tenure.
De Souza represented Benaulim, Calangute and Saligao constituencies before being defeated in the 2007 Assembly election.
He was double Fellow of Royal College of Surgeons at UK. He also received the Dr B C Roy award for best medical man-cum-statesman from former President K R Narayanan in 1996.