It happened around 10:10 a.m. in the 200 block of West Chelten Avenue.
According to police, one private ambulance crew was there to transport a patient, and another private ambulance crew was there to assist.
At one point, the driver of one of those ambulances got out, but then the vehicle started to roll backward.
According to police, the driver jumped back in to stop the vehicle but instead hit the accelerator.
The ambulance quickly backed up, police said, and pinned another worker between the two ambulances.
The woman who was struck was transported to Albert Einstein Medical Center where she was pronounced dead shortly after 11 a.m.
The victim has been identified as 32-year-old Nisha Jaia Renee Dash of the 5800 block of North 15th Street.
There was no word on whether there would be charges in this crash.
Police say the Accident Investigation Division is handling this case.