About 1:50 a.m. he was riding a train in the 100 block of West Cermak Road when a man sitting across from him stabbed him in the face with a knife, causing a laceration, Chicago police said.
He was transported to Stroger Hospital and listed in fair condition, police said.
The other man fled the scene after the attack, according to police. He has gray hair and was wearing black jeans and a black jacket, police said.
Police do not yet know what provoked the stabbing.
Area One detectives are investigating