It happened around 6:20 p.m. along the 1800 block of North Front Street.
Police say a 22-year-old woman was stabbed once on her side and once in her upper back. She was rushed to the hospital, her condition is unknown at this time.
It's unclear what sparked the incident.
No arrests have been made.
Anyone with any information is asked to call police at 215-686-TIPS.