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In order to know the requirements of digestible lysine and sulfur amino acids in White Leghorn hens, two experiments were conducted. Two hundred and forty caged laying hens, Isa Babcock B-300 line, were used in each experiment. The birds were 24 weeks old. Completely randomized designs with 5 treatments were used in both experiments. In Experiment 1, the treatments were 5 amounts of digestible lysine (0.47%, 0.57%, 0.67%, 0.77% and 0.87%), and in Experiment 2 the treatments were 5 amounts of digestible methionine + cystine (0.41%, 0.47%, 0.53%, 0.59% and 0.65%). The basal diets with 15.69% crude protein were based on sorghum + soybean and corn yellow gluten meal. In order to reach the required amino acid levels in the experimental diets, HCl L-lysine and DL-methionine were added. In each experiment, the studied productive parameters that were analyzed by multivariate variance analysis were: laying percentage, egg weight, egg mass per bird per day, feed consumption and feed conversion. The results obtained through 10 weeks of experimentation showed a quadratic effect (P < 0.01), the optimum levels in order to reach maximum productivity were 0.728% of digestible lysine and 0.615% of digestible methionine + cystine with a daily feed consumption per bird of 655 mg of lysine and 553 mg of sulfur amino acids. These results suggest that the ideal relationship for maximum productivity in layer hens is: lysine at 100% and methionine + cystine at 84.4%. [ABSTRACT FROM AUTHOR]