In 1948 and 1949, 1,000 fingerling brook trout of a wild strain and 4,500 fingerlings of a hatchery-developed strain were stocked in Stillwater Pond, a 55-acre pond in Putnam County, New York. All fingerlings were fin-clipped for recognition. Returns from plantings in both years followed similar patterns. Yields from the wild strain were disproportionately low in the first season after planting and disproportionately high in the second season. Field observations indicated that individuals of the two groups were consistently different in appearance and generally could be separated by characteristics of body shape and color. Length-weight data, expressed as condition factors, illustrate morphological differences in trout of the two groups after they had been in the pond for 18 months. Angling returns indicate that better angler satisfaction may be obtained here from stocking trout of both strains together than from stocking either one alone. It is concluded that differences in these two strains of trout as exhibited in this situation are hereditary (racial) and are of sufficient magnitude to be important in management of a brook trout fishery.