this study was conducted to determine the digestible lysine requirement for non castrated pigs of high genetic potential in growth phase. it was used 320 not castrated and 80 castrated males, with initial weight of 27.75±1.61kg, distributed in a randomized block design consisting of five treatments (0.90, 1.00, 1.10 and 1.20% digestible lysine for not castrated and 1.10% digestible lysine for castrated males), eight replicates with ten animals each. the increase of lysine concentration in the diet increased linearly (p<0.05) the final weight, daily lysine intake, daily weight gain and lysine intake per kilogram of weight gain and reduced feed conversion of not castrated males. the treatments did not affected (p>0.05) daily feed intake of not castrated males. castrated males had higher (p<0.05) daily feed intake and lower (p<0.05) feed conversion compared to not castrated fed diets containing 1.00, 1.10 and 1.20% lysine. castrated males had higher daily lysine intake (p<0.05) than not castrated fed diets containing 0.90, 1.00 and 1.10% lysine. castrated pigs had lower (p<0.05) daily gain and final weight in relation to non castrated consuming a diet containing 1.20% lysine. castrated males had higher (p<0.05) lysine intake per kilogram of weight gain compared with not castrated. it is recommended a minimum of 1.20% lysine in the diet of not castrated male pigs with high genetic potential in growth phase.