A baseball uniform is a type of uniform worn by baseball players. Most baseball uniforms have the names and uniform numbers of players who wear them, usually on the backs of the uniforms to distinguish players from each other. Baseball shirts (jerseys), pants, shoes, socks, caps, and gloves are parts of baseball uniforms. Most uniforms have different logos and colors to aid players, officials, and spectators in distinguishing the two teams from each other and the officials. They are made out of polyester instead of cotton, because washing shrinks the cotton fabric.
Baseball uniforms were first worn by the New York Knickerbockers Baseball Club in 1849. Today, sales of replica uniforms and derivative branded products generate large amounts of income for Major League teams through merchandising.
The New York Knickerbockers were the first baseball team to wear uniforms, taking the field on April 4, 1849, in pants made of blue wool, white flannel shirts and straw hats. The practice of wearing a uniform soon spread, and by 1900, all Major League Baseball teams had adopted them. By 1882 most uniforms included stockings, which covered the leg from foot to knee, and were used to differentiate one club from another. The uniforms themselves had different colors and patterns that reflected the different baseball positions. In the late 1880s, the Detroit Wolverines and Washington Nationals of the National League and the Brooklyn Bridegrooms of the American Association were the first to wear striped uniforms.