2003 Major League Baseball season

The 2003 Major League Baseball season ended when the Florida Marlins defeated the New York Yankees in a six-game World Series. The Detroit Tigers set the American League record for losses in a season, with 119, and the Marlins became the first team to win the championship twice as a wild card.

National League
±hosted the MLB All Star Game

Bracket
  Note: Two teams in the same division could not meet in the division series.

Other awards

 * Outstanding Designated Hitter Award: David Ortiz (BOS)
 * Hank Aaron Award: Alex Rodriguez (TEX), American); Albert Pujols (STL), National).
 * Roberto Clemente Award (Humanitarian): Jamie Moyer (SEA).
 * Rolaids Relief Man Award: Keith Foulke (OAK, American); Éric Gagné (LAD, National).
 * Warren Spahn Award (Best left-handed pitcher): Andy Pettitte (NYY)

Television coverage
This was the third season that national TV coverage was split between ESPN and Fox Sports. ESPN and ESPN2 aired selected weeknight and Sunday night games, and selected Division Series playoff games. Fox televised Saturday baseball, the All-Star Game, selected Division Series games, both League Championship Series, and the World Series.

Events

 * April 2 – The Detroit Tigers become the first team to have four pitchers make their Major League debut in the same game. Jeremy Bonderman, Wilfredo Ledezma, Chris Spurling and Matt Roney all played in the 8-1 loss to the Minnesota Twins.
 * May 23 – During the Atlanta Braves 15-3 victory over the Cincinnati Reds, Braves players Rafael Furcal, Mark DeRosa and Gary Sheffield hit consecutive home runs to start the game.
 * June 23 – Barry Bonds steals his 500th career base, becoming the only member of baseball's 500 home run/500 stolen base club