Fire Department spokesman Danny Glover said the body was found in the rubble. Three bodies were found on Wednesday in the immediate aftermath of the blast and three more overnight.
A gas leak triggered the explosion on Park Avenue and 116th Street in East Harlem.
Sixty other people were injured in the explosion and subsequent collapse of the buildings, including three children.
The explosion shattered windows a block away, cast a plume of smoke over the skyline and sent people running into the streets.
Authorities said the fiery blast erupted about 15 minutes after a neighbouring resident reported smelling gas.
One of those killed was identified as a security officer at a Manhattan college. Hunter College president Jennifer Raab said Griselde Camacho had worked there since 2008.
Another victim was identified as dental hygienist Carmen Tanco, 67.