A study was conducted with 1,751 Large White turkeys divided into 36 pens of males and 36 pens of females between 8 and 24 or 20 weeks of age, respectively, to determine the requirements of protein and lysine for turkeys. Diets were composed of ground yellow corn, dehulled soybean meal, 6% stabilized fat, 4% meat and bone meal, .4% methionine, minerals, and vitamins. A 3 X 3 factorial design of nine diets varying in protein (18, 21, and 24%) and added lysine (0, .1, and .2%) was used between 8 and 12 weeks of age. Birds were reassigned to new balanced pens at the end of each 4-week period, and protein levels were reduced by 3.0%. The addition of 3 and 6% protein, which provides .22 and .44% lysine, to diets of turkeys between 8 and 20 weeks of age increased body weight gains 18.3 and 24.7%, respectively, in contrast to an increase of only 2.2 and 3.6% from .1 and .2% added L-lysine per se. the minimum protein requirements of large White male turkeys at 10, 14, and 18 weeks of age are 21.3, 19.5, and 17.6% and for female turkeys 21.7, 18.4, and 15.0%, respectively. The minimum lysine requirements of large White turkeys to 12, 16, and 20 weeks of age are about 1.4, 1.2, and.9%, respectively, or 4.5, 3.7, and 3.0 g/kcal metabolizable energy. Another amino acid appears to be equally or more deficient than lysine in diets used in this study.