A call about the fire at the jeans factory on Tank Road was received at 4.50 am. Five fire tenders were rushed and it was brought under control at 5.10 am, said a Delhi Fire Services official.
The fire had started in a staircase area on the first floor of the building giving out a heavy plume of smoke.
On the second floor of the building, the body of a man identified as Jumman was found. He died due to suffocation, the official said.
The cause of fire is under investigation, police said.
Last month, a fire in a firecracker storage unit in Bawana industrial area had claimed the lives of 17 workers.