Japanese quails (Coturnix coturnix japonica) is gaining popularity as a diversified poultry species. These are reared for eggs and meat production. No new reports on the nutrient requirements for quails have been described since 1984 (NRC, 1994), evidencing the need of new information. The increasing prices of corn and soybean meal and the greater commercial availability of the two most important limiting amino acids for birds (methionine and lysine) have drawn interest to diet formulation based on reduced protein levels with adequate amino acid supplementation. The present study was conducted to investigate the optimum dietary protein level by providing adequate amounts of lysine, methionine, according to the requirements on the performance of quails