The crash happened just after 2 p.m. near the intersection of 49th Street and Fifth Avenue, in front of Saks.
Police said the cab was going south on Fifth Avenue when it side-swiped another cab. It then struck a guardrail and flipped over onto Fifth Avenue.
There were two people in the cab -- the driver and a passenger. Both were taken to a nearby hospital in stable condition.
A crowd gathered around the scene after the crash, and NYPD officers shut down traffic in the area.
Watch video showing the aftermath of the crash in the player above.
Police are investigating the crash.