The team said Killebrew died peacefully Tuesday morning with his wife, Nita, and their family at his side.
He had announced in December that he had been diagnosed with esophageal cancer. Last week, Killebrew announced that doctors had deemed his cancer incurable and he would no longer fight it.
Killebrew hit 573 home runs during his 22-year career, 11th-most in major league history. His eight seasons with 40 or more homers still is tied for second in league history to Babe Ruth.