The crime was caught on surveillance video, released by police on Wednesday morning.
Police say the victim, a 75-year-old woman, had withdrawn $2,700 from a bank around 6:30 p.m. on July 13th.
The victim then went into the CVS store at 1826 Chestnut Street. Also in the store was an unknown man who had been following her.
The woman put her purse, with the $2,700 inside, in a cart as she was in the store. When she stepped away, police said, the suspect pulled the cart away and grabbed the purse.
The man then fled in an unknown direction.
Surveillance video released by police showed the woman returning to her cart and frantically looking around the store for her missing purse.
The suspect is described as a black male of about 40 to 50 years old weighing 230 pounds and standing 5'7" tall. He was bald with stubble on his face, wearing a red t-shirt with YMCA on the front and a number 5 on the back. He also wore tan shorts, white socks and white sneakers.
Anyone with information is asked to contact Philadelphia police at 215-686-TIPS (8477), text a tip to PPD TIP or 773847, or through phillypolice.com.