The theft happened around 9:30 a.m. on February 6th at the Bank of America branch at 2399 Oregon Avenue.
In a news release issued Tuesday, police said the victim withdrew money from that ATM and left, but neglected to close out the transaction.
A short time later an unknown man came up to the ATM and withdrew $700 from the woman's account, which was still open.
The man then left in a silver vehicle.
The suspect is described as a black man in his 50s with a mustache, light beard and a dark complexion. He was wearing gold-trimmed glasses, a gray sweatshirt with logos on the front and back.
Anyone with information is asked contact the Philadelphia Police Department at 215-686-TIPS (8477) or at phillypolice.com.