At about 11 p.m., officers responded to the 2000 block of Palou Avenue, where two men were attacked after the suspects knocked on their front door, San Francisco police spokesman Sgt. Troy Dangerfield said.
"There was some kind of verbal altercation between the people who answered the door and the suspects," and the quarrel turned physical, Dangerfield said.
The man who answered the door was shot, and the second victim, who was also inside the residence, was assaulted, he said.
Police have two male suspects in custody as of 1 a.m., and the investigation is ongoing, Dangerfield said.
The shooting is San Francisco's 36th homicide this year and the first since 38-year-old Asa Roberts was shot in the city's Visitacion Valley neighborhood on Sept. 3.