The robbery happened at 10:42 a.m. at the Beneficial Bank in the 5300 block of Chew Avenue.
Investigators say the suspect robbed the bank with a note demanding money.
The man is described as a black male about 25-30 years old with a light beard. He was wearing black glasses, a black baseball cap, a grey hoodie and brown pants.
Police did not disclose how much money was stolen.
Anyone with information is asked contact the Philadelphia Police Department at 215-686-TIPS (8477) or at phillypolice.com.