Species associations among 48 fish species of the Kiamichi River, a large tributary of Red River in SE Oklahoma, were examined using factor analysis of abundance data for 131 collection localities. Collections with high scores for Factors II and III (Steelcolor Shiner and Brook Silverside Groups) were concentrated in upper portions of the drainage, although certain species of both groups were rather widely distributed over the drainage. Collections with high scores for Factor I (White Bass Group) were primarily restricted to the mainstream of the lower Kiamichi River; those with high scores for Factors V and VI (Silvery Minnow and Golden Shiner Groups) were concentrated in tributaries of the lower Kiamichi. Excepting two species restricted to the lower Kiamichi, the species of Factor IV (Green Sunfish Group) were widely distributed over the drainage. In general, occurrence in the lower Kiamichi was positively correlated with westward distribution of the species into prairie environments of Oklahoma. Apparently, this was due to the ability of many of these species to thrive in lentic waters and/or to their ecological flexibility. Brief consideration is given to factors influencing distributions of species and to possible impacts of reservoir construction on the ichthyofauna of the Kiamichi River.