Officers responded to a report of shots fired in the 2400 block of San Bruno Avenue just after 2 a.m., San Francisco police spokesman Albie Esparza said.
Arriving officers found a man and a woman in their mid 20s who had been shot, Esparza said.
Both victims were taken to San Francisco General Hospital, Esparza said. The male victim's gunshot wounds were potentially life threatening.
Witnesses said a Hispanic man in his early 20s shot the two victims with a handgun and fled.
Anyone with information is asked to contact the San Francisco police anonymous tip line at (415) 575-4444.