The workers became stuck in a deep trench on the 200 block of Temescal Canyon Road near Pacific Coast Highway.
One worker was pulled from the trench at about 3 p.m. The second worker had been unconscious in grave condition in the hole, then died, the Los Angeles City Fire Department said.
Fire department personnel was called to the scene at about 1:40 p.m.
The rescued worker was airlifted to Ronald Reagan UCLA Medical Center in serious condition.
The recovery of the body was expected to take hours.