Seven genera—Brachymystax,Acantholingua,Salmothymus,Hucho,Salvelinus,Salmo, andOncorhynchus—make up the living Salmoninae. Relationships of 33 extant and 4 fossil salmonid species and subspecies were studied on the basis of 119 characters analyzed by parsimony algorithms. Twelve equally parsimonious trees each requiring 253 steps were calculated. Monophyly of recognized genera is consistent with all 12 estimates. The earliest branch of the family Salmonidae is the subfamily Coregoninae. Its sister group is the clade including the Thymallinae and Salmoninae. Within the Salmoninae,Eosalmo, from the Eocene of British Columbia, is the sister group of all living genera, as previously shown by Mark Wilson. The living Asian speciesBrachymystax lenokis the sister species of all other living Salmoninae, as documented by Carroll Norden. Three species of archaic trouts from the Mediterranean area—Acantholingua ohridana,Salmothymus obtusirostris, andSalmothymus(Platysalmo)platycephalus—branch off afterBrachymystaxbut before diversification of all other salmonines.Platysalmo platycephalusBehnke is the sister species ofSalmothymus obtusirostrisand is placed inSalmothymus. The clade beyond the archaic trouts includes four genera in two clades: (1)HuchoplusSalvelinusand (2)SalmoplusOncorhynchus. The Atlantic trouts and salmons are a monophyletic group,Salmo, and the Pacific trouts and salmons are a monophyletic group,Oncorhynchus. The terms “trout” and “salmon” refer roughly to life history modes, not to phylogenetic relationships. Morphological and mitochondrial DNA data disagree regarding the relationship ofOncorhynchus clarki(cutthroat trout) toOncorhynchus mykiss(rainbow, California golden, and redband trouts) and the relationship ofOncorhynchus gorbuscha(pink salmon) toOncorhynchus keta(chum salmon). Parsimony analysis suggests thatOncorhynchus mykissis the sister of the Pacific salmon, not ofO. clarki, thoughO. clarkiandO. mykisshybridize,Oncorhynchus gorbuschais the sister species ofO. nerka(sockeye salmon), not of keta, thoughO. gorbuschaandO. ketahybridize. Mitochondrial DNA is interpreted as having been transferred by introgression betweenO. gorbuschaandO. keta, providing misleading evidence of relationship. Fossil species ofOncorhynchusdocument a minimum age of 6 million years for the modern species of Pacific trouts and salmons.