In rainbow trout, individual and family selection are the most promising selection methods. Since additive genetic variance seems to be present for all economically important traits, selection should always be used in breeding programs, and crossbreeding should be included only when heterosis is large. Since fecundity is high in rainbow trout the breeding program can be concentrated at one or a few breeding centers. The importance of evaluating breeding values of fish under practical farming conditions (test stations) is stressed. Multiplier stations should be developed according to needs. It is concluded that selection is a powerful tool to increase productivity in rainbow trout and that it will increase the rate of domestication.