The following are the baseball events of the year 1990 throughout the world.
Champions
Major League Baseball
Other champions
Awards and honors
MLB Statistical Leaders
Major League Baseball final standings
Events
- April 20: After retiring the first 26 Oakland Athleticsbatters, Brian Holman loses a perfect game when Ken Phelps hits a home run in a eventual 6-1 Seattle Mariners win.
- October 20: The talk of an Oakland Athletics dynasty is proven premature, as the Cincinnati Reds beat Oakland 2–1 to complete one of the most stunning sweeps in World Series history. Series MVP José Rijo (2–0, 0.59 ERA) retires the last 20 batters he faces to give the Reds their first World Championship since 1976. Not joining the celebration at the end is Eric Davis, who ruptures his kidney diving for a ball during the game and is taken to the hospital. It will take Davis several years to fully recover.
- December 6: At Leland's auction house in New York City, Shoeless Joe Jackson's signature is sold for $23,100, the most money ever paid for a 19th- or 20th-century signature. Jackson, who could not read or write, copied the signature from one written out by his wife. The signature, which is resold within hours, was cut from an unknown document.
Deaths
- January 4: Bobby Balcena, 74, outfielder for the Cincinnati Reds, who during the 1956 season became the first player of Filipino ancestry to appear in a major league game.
- January 7: Horace Stoneham, 86, owner of the Giants from 1936 to 1976 who moved the team from New York City to San Francisco for the 1958 season; the team won five NL pennants and the 1954 World Series during his tenure.
- January 9: Spud Chandler, 82, All-Star pitcher for the New York Yankees who was the AL's MVP in a 20-4 season in 1943; owned career .717 winning percentage.
- February 24: Tony Conigliaro, 45, All-Star right fielder for the Boston Red Sox who at age 20 became the younger player ever to win a home run title, but never fully recovered from being hit in the face by a pitch two years later.
- March 6: Joe Sewell, 91, Hall of Fame shortstop for the Cleveland Indians and New York Yankees who batted .312 lifetime and struck out only 114 times in over 8,300 plate appearances; led AL in doubles in 1924, and in putouts and assists four times each.
- March 26: Chet Brewer, 83, All-Star pitcher of the Negro Leagues, later a scout for the Pirates.
- March 29: Phil Masi, 74, a four-time All-Star catcher who played for the Boston Braves, Pittsburgh Pirates and Chicago White Sox between 1939 and 1952.
- April 21: Johnny Beazley, 71, who went 21–6 with a 2.13 ERA in his 1942 rookie season for the Cardinals and pitched two complete-game wins in the team's World Series over the Yankees.
- May 23: Charlie Keller, 73, five-time All-Star left fielder for the New York Yankees who hit 30 home runs three times.
- May 24: Augie Donatelli, 75, National League umpire from 1950 to 1973 who initiated that league's trend toward a low strike zone, and spearheaded the formation of the first umpires' union.
- July 28: Red Barrett, 75, All-Star pitcher for three NL teams who set a major league record for the fewest pitches (58) in a nine-inning game in 1944; led NL in wins in 1945.
- August 10: Cookie Lavagetto, 77, All-Star third baseman who, with the Brooklyn Dodgers, spoiled a Yankee no-hitter with two out in the ninth inning of Game Four in the 1947 World Series, hitting a game-winning double; later managed the Senators and Twins.
- August 28: Larry Jackson, 59, All-Star pitcher who won 194 games for the Cardinals, Cubs and Phillies; led NL in wins in 1964.
- September 9: Doc Cramer, 85, five-time All-Star center fielder for four AL teams who collected 2,705 hits and was a defensive standout; the only AL player to twice go 6-for-6 in a nine-inning game.
- October 10: Wally Moses, 80, All-Star right fielder for the Athletics, White Sox and Red Sox who hit .300 in his first seven seasons, led AL in doubles and triples once each.
- November 8: Earl Torgeson, 66, first baseman who hit .389 in 1948 World Series with Boston Braves, led NL in runs in 1950.
- November 10: Aurelio Monteagudo, 46, Cuban pitcher with five teams who also gained renown pitching in the Venezuelan and Mexican leagues.
- November 22: Joe Bowman, 80, pitcher for the Athletics, Giants, Phillies, Pirates, Red Sox, and Reds between 1932 and 1945.
- November 23: Baudilio "Bo" Díaz, 37, All-Star catcher, most notably with the Phillies and Reds, who batted .333 in the 1983 World Series.