The victim was stabbed in the left arm and left rib while riding the subway just before 9:45 a.m.
He reportedly had gotten into a "stare down" with another person on the train as they rode south from the Bronx.
A scuffle ensued, and the two were quickly broken up.
When the victim got off at the 59th Street-Columbus Street subway station, he realized he had been stabbed.
He walked to nearby Roosevelt Hospital and was being treated.
No arrests were immediately made and service was not disrupted.
