The San Rafael River and lower reaches of four major tributaries, Cottonwood, Huntington, Ferron, and Rock Canyon creeks, were sampled for fish and water quality in March-April, June, and October, 1977. Native species of fish included speckled dace (Rhinichthys osculus), flannelmouth suckers (Cato- stomus latipinnis), bluehead suckers (C. discobolus), and roundtail chubs (Gila robusta). Red shiners (Notropis lutrensis), fathead minnows (Pimephales prom- elas), black bullheads (Ictalurus melas), and channel catfish (I. punctatus) were recorded introduced species. A single young-of-the-year Colorado squawfish (Ptychocheilus lucius) was caught in the lower San Rafael River in October. This is the first documented record of Colorado squawfish in the San Rafael River. Native fish were dominant at seven stations in the tributary streams and middle section of the San Rafael River and introduced fish dominated the fauna near the mouth of the river.