- February 3 - The Hall of Fame's Special Committee on the Negro Leagues picks versatile Cuban star Martin Dihigo and shortstop John Henry Lloyd for induction. The committee then dissolves, its functions being taken over by the Veterans Committee.
- March 21 - Mark Fidrych, the 1976 AL Rookie of the Year, rips the cartilage in his left knee and will undergo surgery in ten days. The injury will effectively end the fabled career of The Bird.
- August 17 - Records fall as the Mexican League concludes its season. Ironman reliever Aurelio López of the Mexico City Reds racks up his 30th save to go with a record 19 victories in relief. Veteran Tampico first baseman Héctor Espino hits 14 home runs, raising his career total to 435, a new minor league record. Thirty-eight-year-old Vic Davalillo, the league's top hitter with a .384 batting average, is purchased by the Dodgers.
- August 31 - Hank Aaron's major league mark of 755 career home runs is tied by Sadaharu Oh in Japanese baseball. Three days later, Oh will hit his 756th homer to surpass Aaron's total, becoming the most prolific home run hitter in professional baseball history.
- September 6 - The California Angels acquire slugger Dave Kingman for cash consideration. Nine days later, the New York Yankees will buy Kingman, making him the first player to wear four uniforms in four divisions during the same season. His 26 home runs will be the most by a player with more than two teams.
- January 1 - Danny Frisella, 30, relief pitcher who saved 57 games for five teams
- January 11 - Tex Carleton, 70, pitcher who won 100 games, including a no-hitter, for Cardinals, Cubs and Dodgers
- January 16 - Baby Doll Jacobson, 86, center fielder for the St. Louis Browns who batted .311 lifetime
- January 29 - Hod Ford, 79, infielder for fifteen seasons with five NL teams
- February 4 - Nemo Leibold, 84, outfielder for four AL teams batted .300 twice; later a minor league manager
- April 12 - Philip K. Wrigley, 82, owner of the Chicago Cubs since 1932, and vice president of the National League from 1947 to 1966; also organized the All-American Girls Professional Baseball League in 1943
- April 28 - Al Smith, 69, All-Star pitcher who won 99 games for Giants, Phillies and Indians
- June 10 - Turk Farrell, 43, All-Star pitcher who won 106 games, mainly with the Phillies and Astros
- June 15 - Big Bill Lee, 67, All-Star pitcher who had two 20-win seasons for the Chicago Cubs
- July 16 - Milt Stock, 84, third baseman who batted .300 five times
- September 2 - Chucho Ramos, 59, Venezuelan outfielder who played 4 games for the 1944 Cincinnati Reds
- September 8 - Oral Hildebrand, 70, All-Star pitcher who won 83 games for the Indians, Browns and Yankees
- September 14 - Beau Bell, 70, All-Star right fielder who led AL in hits and doubles in 1937; later coached at Texas A&M
- September 24 - Sherm Lollar, 53, 7-time All-Star catcher for the Chicago White Sox who won first three Gold Gloves awarded
- September 26 - Ernie Lombardi, 69, 8-time All-Star catcher, mainly with the Cincinnati Reds and New York Giants, who batted .306 lifetime and won 1938 MVP award; only catcher to win two batting titles, he caught Johnny Vander Meer's back-to-back no-hitters in 1938
- September 30 - Del Pratt, 89, second baseman for four AL teams who led AL in RBI in 1916 with St. Louis Browns; batted .300 in his last five seasons
- October 17 - Cal Hubbard, 76, Hall of Fame umpire in the American League from 1936 to 1951 who developed modern systems of umpire positioning
- November 8 - Bucky Harris, 81, Hall of Fame manager of five teams who won 3rd most games (2157) in history; managed Senators three times, winning 1924 World Series as rookie skipper, and also led Yankees to 1947 title; as second baseman, led AL in double plays five times
- November 9 - Fred Haney, 79, manager who won World Series with Milwaukee Braves in 1957; was Angels' first general manager from 1960–68
- November 17 - Roger Peckinpaugh, 86, shortstop for four AL teams who was named the 1925 MVP in his last full season; became manager and general manager of the Indians
- November 24 - Mayo Smith, 62, manager of the Phillies, Reds and Tigers who led Detroit to the 1968 World Series title
- November 28 - Bob Meusel, 81, outfielder, mainly with the Yankees, who batted .309 lifetime and led AL in HRs and RBI in 1925; hit for the cycle three times
- December 1 - Dobie Moore, 82, star shortstop for the Negro Leagues' Kansas City Monarchs
- December 29 - Jimmy Brown, 67, All-Star infielder and leadoff hitter for the St. Louis Cardinals