Police said the woman, identified as Frances Thelen of the first block of Shipping Place, was pulled from the water off the 300 block of Light St. about 8:15 p.m.
Thelen was taken by ambulance to Mercy.
One of the victim's rescuers was Wayne McClanan, 36, a light-heavyweight boxer from Virginia Beach, Va., who is on a fight card tonight at the Baltimore Arena.
McClanan, scheduled to fight David Izegwire of Washington in a six-rounder, said he was with several other fighters near Phillips Restaurant at Harborplace when he saw a woman jump from a pier.
"I was about 50 yards away from her and I just sprinted and jumped in," McClanan said. "When something like this happens you just react."
He and two other people, identified by police as Bob Joyce, 28, of 1600 block of Shakespeare St., and Glenn Schuster, 26, of the 2000 block of Fountain St., both in Fells Point, pulled the woman out of the water and got her back on shore within minutes.
McClanan said the woman appeared to be very upset and distraught.
"She was saying that she didn't want to live and wanted to die," he said. "I told her she had a lot to live for and it's always better than dying."