When did the number of baseball games in a season change?

Answer 1

Prior to 1961, teams in the American League played 154 game seasons. When two new expansion teams were added, the Los Angeles Angels and the Washington Senators, the schedule was increased to 162 games. Prior to 1962, teams in the National League played 154 game schedules. When two new expansion teams were added, the Houston Colt 45s and the New York Mets, the schedule was increased to 162 games.

Answer 2

Between 1904-1960 MLB's schedule was 154 games. Since 1961 MLB's schedule has been 162 games.