Nematodes from the swimbladder of Oncorhynchus species are assigned to two genera: Cystidicola Fischer, 1798, and Salvelinema Trofimenko, 1962 (syn. Pseudometabronema Bogdanova, 1963). Cystidicola is represented in Asia by C. farionis Fischer, 1798 (syn. C. impar (Schneider, 1866)); specimens of this genus from Alaska could not be specifically identified because of immaturity. Cystidicola sligmatura (Leidy, 1886} occurs in North America within the range of Oncorhynchus but has not been found in this genus of fishes. Two species of Salvelinema are recognized: S. salmonicola (Ishii, 1916) Margolis, 1966, from Asia and North America, and S. walkeri (Ekbaum, 1935) n. comb, from North America. These two Salvelinema species and the immature Cystidicola sp. are described. Synonyms of S. salmonicola are Oxyuris sp. Koshida, 1905; Ancyracanthus s. Ishii, 1916; Cystidicola s. (Ishii, 1916) Fujita, 1927; Cystidicola chitosensis Fujita, 1940; "C. farionis" of Zhukov, 1960; S. cristata Trofimenko, 1962; and Pseudometabronema sachalinense Bogdanova, 1963. Synonyms of S. walkeri are Cystidicola walkeri Ekbaum, 1935, and "C. stigmatura" of Haderlie, 1953. Host and geographical distribution of the swimbladder nematodes of Oncorhynchus are reviewed.