We present an extensive and up-to-date catalog of Galactic {beta} Cephei stars. This catalog is intended to give a comprehensive overview of observational characteristics of all known {beta} Cephei stars, covering information until 2004 June. Ninety-three stars could be confirmed to be {beta} Cephei stars. We use data from more than 250 papers published over the last nearly 100 years, and we provide over 45 notes on individual stars. For some stars we reanalyzed published data or conducted our own analyses. Sixty-one stars were rejected from the final {beta} Cephei list, and 77 stars are suspected to be {beta} Cephei stars. A list of critically selected pulsation frequencies for confirmed {beta} Cephei stars is also presented.