The stabbing was reported at 11:20 p.m. in the 100 block of Jones Street.
The victim was approached by a man believed to be in his 50s and an argument ensued, according to police.
At some point, the suspect pulled out a knife and stabbed the victim in the shoulder and hand and then fled, police said.
The victim was taken to San Francisco General Hospital to be treated for his injuries, which are not life-threatening, police said.
The suspect remained at large as of this morning. Anyone with information about the case is asked to call the Police Department's anonymous tip line at (415) 575-4444 or send a tip by text message to TIP411 with "SFPD" in the message.