It happened shortly before 6:00 p.m. on Wednesday.
Investigators say the victim was walking home from the Farmers Market when, in the 2300 block of Manning Street, the bicyclist came up behind her.
The man grabbed her by the back and spun her around, injuring her right knee.
The victim began to scream, police say, and that's when the suspect grabbed her purse, which had her driver's license, credit cards, pre-paid cell phone and $65 in cash.
The man then rode his bike west on Manning Street.
"He might not be part of that community," said Lt. Patrick Doherty of the Philadelphia Police. "But whatever community he lives in, he's a problem. He's doing burglaries, he's doing thefts, car thefts, auto thefts. It would benefit everyone in Philadelphia if we would get this guy identified and off the street.
The head of maintenance at the building that provided the surveillance video, John Stevenson, was disgusted by what was captured by the cameras.
"He's less than a man, that's what I say," Stevenson said. "You don't do that anyway, but an older lady? C'mon. A punk."
The suspect is described by police as a black male, about 20 years old, standing six feet tall with a muscular build. He was wearing a bright green t-shirt and tan shorts.
Anyone with information is asked to contact Philadelphia Police at 215-686-TIPS (8477), text a tip to PPD TIP (773847) or through PhillyPolice.com.