The Arizona Diamondbacks are an American professional baseball team based in Phoenix, Arizona. The Diamondbacks compete in Major League Baseball (MLB) as a member of the National League (NL) West Division. The franchise was established on March 9, 1995, and began play in 1998 as an expansion team. The team plays its home games at Chase Field. Along with the Tampa Bay Rays, the Diamondbacks are one of the newest teams in MLB and are the youngest team to win the World Series.

Major League Baseball (MLB) is a professional baseball league and the highest level of organized baseball in the United States and Canada. One of the big four major leagues, MLB comprises 30 teams, divided equally between the National League (NL) and the American League (AL), with 29 in the United States and 1 in Canada. Formed in 1876 and 1901, respectively, the NL and AL cemented their cooperation with the National Agreement in 1903, making MLB the oldest major professional sports league in the world. They remained legally separate entities until 2000, when they merged into a single organization led by the Commissioner of Baseball. MLB is headquartered in Midtown Manhattan.