Offseason
- October 8, 1958: Hobie Landrith, Billy Muffett and Benny Valenzuela were traded by the Cardinals to the San Francisco Giants for Marv Grissom and Ernie Broglio.
- October 15, 1958: Marshall Bridges was purchased by the Cardinals from the Sacramento Solons.
- December 1, 1958: Johnny O'Brien was drafted from the Cardinals by the Philadelphia Phillies in the 1958 rule 5 draft.
- December 3, 1958: Rubén Amaro was traded by the Cardinals to the Philadelphia Phillies for Chuck Essegian.
- December 4, 1958: Wally Moon and Phil Paine were traded by the Cardinals to the Los Angeles Dodgers for Gino Cimoli.
- March 25, 1959: Sam Jones and Don Choate were traded by the Cardinals to the San Francisco Giants for Ray Jablonski and Bill White.
- Prior to 1959 season (exact date unknown)
- Solly Hemus was signed as a free agent by the Cardinals.
- Lee Gregory was signed as an amateur free agent by the Cardinals.
Read more about this topic: 1959 St. Louis Cardinals Season