Barasat Court's Additional District Judge (6th court) Anirban Das handed down the sentence to Rahman who was arrested in 2002 with 53.5 kg of heroin.
The court also sentenced Deepak Giri, Rahman's aide in the crime, to 30 years rigorous imprisonment.
Rahman was arrested by the Narcotics Control Bureau (NCB) in October 2002 from Salt Lake area and 53.5 kg of heroin with street value of nearly Rs 50 crore was seized from his possession.
Rahman used to travel to several other neighbouring countries to sell narcotics.