Kariya, who spent the previous two seasons in Nashville, had 24 goals and 52 assists in 82 games for the Predators last season. The 32-year-old will provide an instant spark to a Blues team that ranked near the bottom of the NHL with just 214 goals scored.
"We are excited to announce we have signed a world class hockey player as well as a first class person," Blues president John Davidson said in a statement. "Paul gives us instant scoring up front as well as bringing an entertaining brand of hockey to the St. Louis Blues."
Terms of the deal weren't released. Kariya made $US4.5 million last season.
Kariya brings an impressive resume to St. Louis, including two Lady Byng awards as the league's most gentlemanly player, a pair of 100-point seasons and a Stanley Cup final berth with the Anaheim Ducks in 2003. Kariya spent his first seven seasons with Anaheim after being selected in the first round (fourth overall) in the 1993 draft.
The five-foot-10, 176-pound winger is the latest star to leave Nashville, which remains a franchise in flux as owner Scott Leipold looks to sell the team after years of losing money. Forward Scott Hartnell and defenceman Kimmo Timonen were traded to the Philadelphia Flyers last month for a first-round draft pick. A few days later, starting goaltender Tomas Vokoun was shipped to the Florida Panthers for a 2008 first-rounder and a pair of second-round picks.
The Kariya signing capped a big weekend for the Blues, who signed winger Keith Tkachuk to a multi-year deal Saturday after re-acquiring him in a trade with the Atlanta Thrashers earlier in the week.
Kariya has 366 goals and 500 assists in 821 career games with Anaheim, Colorado and Nashville.