Nikolai Khabibulin stopped 22 shots as the Blackhawks, 0-3-2 in their previous five contests, ended St. Louis' four-game winning streak.
Before the game, the Blues traded forward Keith Tkachuk to the Atlanta Thrashers for forward Glen Metropolit, a first-round draft pick in 2007 and two other picks.
Duncan Keith, Adrian Aucoin and Bryan Smolinski scored in the first period for Chicago as the Blackhawks converted three of their first five shots against goalie Curtis Sanford to build a 3-0 lead. Patrick Sharp added a short-handed, empty-net goal with 3:16 left.
Sanford stopped four of 11 shots before being replaced by Jason Bacashihua at the start of the third period. Bacashihua stopped all five shots he faced.