The 2011 National League Division Series (abbreviated NLDS) were two best-of-five playoffs comprising the opening round of the Major League Baseball postseason, played to determine the participating teams in the 2011 National League Championship Series. Three divisional winners and a fourth team—a wild card—played in two series. TBS televised all games in the United States (except Game 3 of the Brewers–Diamondbacks series, which aired on TNT due to scheduling conflicts with the ALDS). The regular season finished on September 28, with the National League playoffs beginning October 1.

Under MLB's playoff format, no two teams from the same division were matched up in the Division Series, regardless of whether their records would normally indicate such a matchup. Home field advantage went to the team with the better regular-season record with the exception of the wild card team, which defers home field advantage regardless of record. The matchups are:

The Phillies and Cardinals played against each other in the postseason for the first time. The Brewers and Diamondbacks also met for the first time, having both joined the National League in 1998—Arizona as an expansion team and Milwaukee in a move from the American League after the AL expanded by adding the Tampa Bay Rays. The Brewers-Diamondbacks series was also notable as the first postseason series played between two teams in ballparks with retractable roofs.

This is the first time since the strike-shortened 1981 season that both National League Division Series matchups went to a deciding Game 5 (it happened to the American League in 2001).

St. Louis Cardinals won the series, 3–2.

Milwaukee Brewers won the series, 3–2.

5:07 p.m. (EDT) at Citizens Bank Park in Philadelphia, Pennsylvania

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