Police responded to the midtown Manhattan landmark at about 2:50 p.m. after a telephone caller to emergency services reported seeing a leg on 33rd Street. After closing the street between Fifth and Sixth Avenues, they discovered that the body had landed on a setback on the 30th floor.
The name of the victim, a lawyer in his 30s, was not immediately released.
Detectives on the street were photographing the leg, which was severed below the knee with the foot still covered in a dark gray sock.
In February 2006, a 21-year-old New York man jumped to his death after buying a ticket to its observation deck. Dovid Abramowitz jumped from a vacant office on the 66th floor of the 102-story building.
More than 30 people have committed suicide at the Empire State Building since it opened in 1931. The skyscraper reaches 1,454 feet to the top of its lightning rod.