Police say the woman was crossing the street near the intersection of Fulton Avenue and Peninsula Boulevard in Hempstead when she was struck around 4 p.m.
She was rushed to Nassau University Medical Center, where she is listed in serious condition.
She suffered serious head trauma.
Police located the suspect's vehicle several blocks away abandoned. The driver apparently took off on foot.
Police are interviewing witnesses to the accident right now, and the investigation is ongoing.