Officers were called to the 1100 block of Palou Avenue around 1:30 p.m. on reports of a triple shooting, police spokesman Officer Gordon Shyy said.
Witnesses reported seeing the victims drive themselves to the hospital, and a short time later, two women and a man arrived at San Francisco General Hospital with gunshot wounds, Shyy said.
He said he did not know the extent of their injuries.
According to police, three male suspects were seen fleeing the area in a white vehicle. No arrests had been made in connection with the shooting as of 3:30 p.m.