Five experimental groups of male weanling albino rats were fed adequate diets containing 12 percent protein for a period of 28 days. Peanut flour and corn gluten meal proteins were combined with turkey protein in the ratio of 9 percent to 3 percent, respectively. The supplementary value of turkey protein to intact natural proteins was determined by comparing the growth rates from the different groups of animals. Best growth, 92.3 gms., was obtained when feeding an adequate diet containing 12 percent turkey meat protein. Corn gluten meal, when fed at the 12 percent level,, produced the poorest weight gain, 17.4 gms. Supplementation of the corn gluten meal with turkey meat increased the growth approximately 100 percent to 33.8 gms. Gain in weight obtained when feeding 12 percent peanut flour, 88.2 gms., was close to that obtained for the turkey protein. Supplementation of the peanut flour with turkey protein produced a decrease in growth of the animals. The PER values found were 3.0 for turkey meat, 0.9 for corn gluten meal, 2. 9 for peanut flour, 1.5 for corn gluten supplemented with turkey meat, and 2.1 for peanut flour supplemented with turkey meat. / Master of Science