Both native and plauted fish of two species of trout were studied to determine the extent of variations in the condition. Brook trout (Salvelinus fontinalis) from eastern streams apparently have a lower norm of condition than rainbow trout (Salmo irideus). Hatchery fish appear to be handicapped, even when planted in a stream exceptionally rich in food, possibly because hatchery conditions prevent them from developing fully their natural foraging ability. Small streams, although rich in food, are unable to supply the normal food requirements of larger fish. A loss was demonstrated in the condition of adult trout planted in the spring for immediate removal. In the appraisal of streams for stocking, it seems that valuable information may be obtained by an analysis of the condition of the native fish.