The suspect entered the Wells Fargo Bank at 4315 Mission Blvd. shortly before 12:30 p.m. and handed the teller the note demanding cash, according to San Diego police Officer Dan Lasher.
The suspect received an undetermined amount of money and fled on foot, the officer said.
Police described the robber as white, in his 30s and about 5 feet 9 with a medium build. He was wearing dark clothing and a black cap.