Six fire Brigade personnel, including two officers, were also injured while carrying out rescue and firefighting operations.
The fire started on the 12th floor of the 26-storey Mont Blanc building in upscale Kemps Corner area. Huge flames were seen emanating from the floor.
"Seven residents from the building have died in the blaze. Identification of some of the residents have been made, while the others could not be identified as they have been badly burnt. The victims were declared dead in the BMC-run Nair Hospital," the official said.
The injured firemen are being treated in the civic-run medical facility and also National Burns Centre & General Hospital at Airoli in adjoining Navi Mumbai.
The cooling operation on the gutted floor are still underway, he said.
Fourteen fire engines, aided by seven water tankers, battled for several hours to putout the inferno. The cause of the fire was not yet known.