The fire broke out at about 2:30 p.m. Thursday in the rear of a home at 44 West 10th Street, and spread to three other attached row homes.
Flames and heavy smoke were seen pouring from the structures, but by nightfall firefighters had the fire under control.
The families living in the homes were able to escape, and no injuries were reported.
Family members gathered in a bus that was sent to the site.
Eyewitness News was told that a contractor doing welding work accidentally started the fire.
West 10th Street was completely shut down from Avenue C to Broadway due to the fire department activity. The Red Cross is helping 7 families, who were displaced by the fire. Those families are from 3 of the buildings. The family living in the fourth was able to go back home Thursday night.