The robbery happened around 1:00 p.m. at the Sovereign Bank branch at 6740 Germantown Avenue.
Police say the man, wearing a dark gray wig, a long-sleeve buttoned shirt and a floral print skirt, came into the bank armed with a gun.
The man demanded cash, which he placed in a purse he was carrying.
Then the suspect fled in a four-door black sedan on Slocum Street.
The man is described as a black man in his late 30's to early 40's.
The man is considered armed and dangerous.
Anyone with information is asked to call the FBI at 215-418-4000 or the Philadelphia Police Department. There may be a reward for information leading to this subject's capture, and tipsters can remain anonymous.