Additional Sessions Judge GP Thareja had earlier pronounced Sushil Sharma – the once influential president of the New Delhi unit of Youth Congress - of murdering his wife Naina Sahni in 1995 and then trying to dispose off her body by burning it in the barbeque grill of a restaurant that he owned.
The judge handed down the sentence on Friday.
Sharma's plans to dispose off his wife's corpse was foiled when the police raided the restaurant and retrieved the charred body parts from the oven.
Youth Congress is the youth wing of the Congress, India's main opposition party headed by Sonia Gandhi.
Sharma killed his wife on suspicion that she was having an extra-marital affair.
The grisly murder led to an eight year trial, evoking unprecedented media interest. While awaiting trial, Sharma had been imprisoned in Delhi's Tihar jail.
Keshav Kumar, the manager of Sharma's restaurant, has also been sentenced to seven years rigorous imprisonment for conspiring to dispose off the body.
Death sentences in India, which are normally carried out by hanging, are rare.
Television channels quoted Sharma's lawyers as saying they would appeal against the sentence.