The 10-year-old plunged down the uncovered utility hole at 13th Avenue near 49th Street around 8:40 a.m., police and fire officials said.
Verizon workers Tom Prestia and Mike Kroski said they were passing by the scene when they saw a crowd gathered around the manhole, according to reports.
The two then used a ladder to pull the boy to safety.
"Once we put those lines down there he came right up. We told him to go slow, I grabbed him and pulled him out," Kroski told NY1.
"I was just glad we were in the right place at the right time," Prestia said.
The boy was taken to Lutheran Medical Center in stable condition with a minor injury to his leg, a law-enforcement official said.
DEP officials said they did not immediately know what caused the manhole cover to come off the lid, but said they found it broken and lying inside the sewer line below the street after the incident. DEP crews were on scene working to repair it, officials said.