A forest ranger told police he was patrolling part of the area when he stumbled on the body that had decomposed on Monday, April 17 morning.
The ranger called the police who picked up the body at the mortuary.
Police said they suspect the deceased who did not have identification documents then died more than four days earlier.
The body was found within the Lenana Ngong Road forest.
Police handling the case say they are yet to know if the man died by suicide or was killed.
A probe into the incident is ongoing.
Cases of suicide have been on the rise amid calls to address the trend.
