Killebrew last year said he has been diagnosed with esophageal cancer and last week said he was entering hospice care. Family members said Killebrew died Tuesday with his wife, Nita, and other family members at his side.
Killebrew broke into the major leagues with the Washington Senators in 1954 and moved with the team to Minnesota, where the team became the Twins, in 1961. He stayed with that franchise through the 1974 season and played one year in Kansas City before retiring.
He was voted the American League's most valuable player in 1969 when he led the league with 49 home runs and 140 runs batted in. He had eight seasons in which he hit a least 40 home runs and ended with 573 homers and a batting average of .256. He was named to the AL All-Star team 11 times.
At the time of his retirement, only Babe Ruth hit more home runs in American League games. Killebrew was elected to the Baseball Hall of Fame in 1984.
He was born June 29, 1936, in Payette, Idaho, and made his major league debut six days before his 18th birthday.
The Twins retired Killebrew's No. 3 uniform number and a street along the Mall of America, which was the site of Metropolitan Stadium before the team moved to the Metrodome, was named "Killebrew Drive." The landing spot of a 520-foot home run -- the longest in team history -- he hit on June 3, 1967, is marked with a red chair hanging on the wall inside the Mall of America.