Paddy Gallagher, Shoemaker's assistant in his years as a trainer, said the Hall of Fame jockey died in his sleep.
The 4-foot-11, 98-pound Shoemaker rode the winners of 11 Triple Crown races. He rode 40,350 horses, won with 8,833 of them, ran second 6,136 times and finished third 4,987 times.
He was the leading U.S. jockey in money won ten times; five times he was the leading jockey in races won.
Shoemaker was paralyzed in an auto accident in 1991 at age 59 and spent the rest of his life training horses from his electric wheelchair.
"I was lucky," he said at his first news conference after the car crash, the New York Times reported. "I rode for 40 years, in 40,000 races, and had a lot of falls. But I never had any spinal injuries or anything like that. Then an automobile got me. So, you never know."