A panhandler stabbed a 76-year-old man during a weekend argument on subway steps in Herald Square, cops say. 

The senior was on the steps leading to the Manhattan subway station at West 35th Street and Sixth Avenue around 11:30 p.m. Sunday when he clashed with the vagrant, whom he did not know, police said. 

The suspect stabbed him once in the right side of his chest by his armpit, authorities said. 

He was taken to Bellevue Hospital, where he was listed in stable condition. 

His attacker fled and has not been caught.

The exact nature of the dispute between the two men was unclear.