Major League Baseball on Mutual was the de facto title of the Mutual Broadcasting System's (MBS) national radio coverage of Major League Baseball games. Mutual's coverage came about during the Golden Age of Radio in the 1930s, '40s, and '50s. During this period, television sports broadcasting was in its infancy, and radio was still the main form of broadcasting baseball. For many years, Mutual was the national radio broadcaster for baseball's All-Star Game and World Series.