A total of 734 male 36-day-old BUT Big 6 turkeys were allotted to 6 groups with 6 replicates each and were fed diets supplemented with graded methionine levels of 0, 0.4, 0.8, 1.3, 1.8, or 2.4 g/kg, respectively. During four weeks of experimental feeding the weight gain of turkeys was proportional to the contents of methionine+cysteine in diets and consistent with the non-linear regression equation Y = 3279 + 363 × (1-d ^{(-12.33 ×(X – 0.607))}), r² = 0.99. Nitrogen retention of the turkeys indicated a trend towards an increase in the amount of retained nitrogen with increasing methionine+cysteine level. The weight gain response suggested that optimum dietary methionine+cysteine levels are higher than 0.80 g/MJ ME, while feed conversion was not affected.