two experiments were carried out to determine the total lysine requirement of purebred landrace swine, males and females, from 15 to 30 kg live weights. fifty females and fifty males were used in a randomized complete block design, with five treatments, five replications and two animals per experimental unit, in the experiments i and ii, respectively. the treatments consisted of a basal diet, supplemented with five levels of l-lysine.hcl, resulting in diets with .85, .95, 1.05, 1.15, 1.25% of total lysine in both experiments. in experiment i, the dietary lysine levels did not influence the average daily feed intake. the average daily gain, daily lysine intake and protein deposition rates in the carcass linearly increased with the lysine level. the treatments quadractily influenced the feed:gain ratio, which improved up to 1.08% lysine level. in the experiment ii, lysine level did not influence the average daily feed intake and the feed:gain ratio. there was a quadratic effect of dietary lysine level on average daily gain, average daily lysine intake and protein deposition rate in the carcass. the best results of average weight gain were obtained with the level of 1.08% lysine. the total lysine requirement, for the starting growing phase (15 to 30 kg), was estimated to be 1.08%, for both sexes.