A passer-by phoned triple zero after finding the woman alone on the footpath of Victoria Road near Adelaide Street, police said.
The woman, who is believed to live near the intersection where she was found, had severe swelling to her face and other head injuries.
Paramedics treated her at the scene before taking her to Westmead Hospital. She died a short time later, police said.
The Metropolitan Crash Investigation Unit set up a crime scene and commenced an investigation
On Monday morning a NSW Police spokesman said it was unclear how the woman was injured. He said it was possible that she had been bashed, or been involved in a car crash.
“We’re not ruling out anything at this stage,” he said.
A 53-year-old woman attended Ryde Police Station and was charged with negligent driving occasioning death and not giving way to a pedestrian on the road. She was granted bail and is expected to appear in Ryde Local Court on 27 June.