Relative growth and survival of offspring from matings of hatchery and wild Deschutes River (Oregon) summer steelhead trout were measured to determine if hatchery fish differ genetically from wild fish in traits that can affect the stock-recruitment relationship of wild populations. The fish used in this study were indigenous to the Deschutes River and the hatchery fish were two generations removed from the wild parental stock. Sections of four natural streams and a hatchery pond were each stocked with genetically marked (lactate dehydrogenase genotypes) eyed eggs or unfed swim-up fry from each of three matings: hatchery x hatchery (HH), hatchery x wild (HW), and wild x wild (WW), In streams. WW fish had the highest survival and HW fish the highest growth rates. In the hatchery pond, HH fish had the highest survival and growth rates. The hatchery fish were genetically different from wild fish and when they interbreed with wild fish may reduce the number of smolts produced. The observed differences in survival suggested that the short-term effect of hatchery adults spawning in the wild is the production of fewer smolts and ultimately, fewer returning adults than are produced from the same number of wild steelhead spawners.