Officers responded to the collision at Powell and Vallejo streets around 12:35 p.m., according to police.
Further details about the victim were not immediately available.
Streets in the area have been closed off as of 2 p.m., police said.
Earlier today, just a block away, a motorcyclist died after colliding with a vehicle at Broadway and Stockton Street just before 6 a.m., police said.
The motorcyclist was taken to a hospital and died there. The person's identity has not been released.
The driver of the other vehicle involved in the morning collision stayed at the scene and is cooperating with investigators, according to police.