The film had received 11 nominations. The film has received 10 Oscar nominations whic is slated on Feb 22.
Rehman received the best music director award and India's Resul Pookutty received the prize for the best sound for the same film along with Glenn Freemantle, Richard Pryke, Tom Sayers and Ian Tapp. Danny Boyle, who directed the film based in the slums of Mumbai was named best director.
However, the film's 18-year-old star Dev Patel lost to Mickey Rourke (The Wrestler) in the best actor category. Patel is also nominated in the best actor category for the Oscars.
"It is in response to a billion prayers. I'm waiting for the big day," said Rahman while dedicating the award to the people of Mumbai.
Slumdog writer Simon Beaufoy, who was awarded the prize for best adapted screenplay, thanked Indian diplomat Vikash Swarup for his novel Q and A, on which the film was based.
"It is a great privilege to have won the award," Beaufoy said.
OneIndia news (With inputs from Agencies)&13;