The crime happened at about 2:51 a.m. near the CTA Red Line 69th Station, police said.
A 34-year-old man got into an argument with an unknown suspect, police said.
The suspect then stabbed the victim in the chest.
The victim was taken to U of C Hospital in serious condition, according to police.
Nobody is in custody.
Chicago police are investigating.
INTERACTIVE SAFETY TRACKER Track crime and safety in your neighborhood