1942 Major League Baseball season

The 1942 major league baseball season began on April 14, 1942. The regular season ended on September 27, with the St. Louis Cardinals and New York Yankees as the regular season champions of the National League and American League, respectively. The postseason began with Game 1 of the 39th World Series on September 30 and ended with Game 5 on October 5. In the third iteration of this World Series matchup, the Cardinals defeated the Yankees, four games to one, capturing their fourth championship in franchise history, since their previous in 1934. Going into the season, the defending World Series champions were the New York Yankees from the 1941 season.

The tenth Major League Baseball All-Star Game was played on July 6 at the Polo Grounds in New York, New York, home of the New York Giants. The American League won, 3–1.

In the National League, the Brooklyn Dodgers had a record of 104–50, but finished two games behind the Cardinals; the Dodgers tied the 1909 Chicago Cubs, who had a record of 104–49, for the most wins in an MLB regular season without reaching the postseason.

The Philadelphia Athletics set a record for the fewest runs batted in during a season, with only 354.

The St. Louis Browns nearly moved to Los Angeles, California for the start of the 1942 season. During the 1941 Winter Meetings in Chicago, Illinois, a vote was scheduled for the morning of December 8, and was expected to be approved. However, due to the attack on Pearl Harbor by Japan the previous day (and subsequent entry of the United States into World War II), when it came time to vote, all teams (including the Browns) unanimously voted against the move. The team would eventually leave for Baltimore, Maryland in 1954 where they remain today as the Baltimore Orioles, while Los Angeles would eventually get a major league team in 1958 when the Dodgers moved from Brooklyn, New York.