1. Diets containing 100 (AA100), 95 (AA95), 90 (AA90) or 85% (AA85) of National Research Council (NRC, 1994) recommendations of methionine, threonine and lysine in a low-protein diet (200 g/kg) were fed to 15-d-old quails. 2. Decreases of up to 15% of NRC recommendations in these three amino acids did not affect feed intake, weight gain and gain:feed intake values in the 15-35- and 15-42-d feeding periods. 3. Compared to control diet, feeding cost per bird was lower in males fed with AA95 and AA85 at 15-35 d and with AA85 diets at 15-42 d. At 15-35 d, feeding cost per 100 g weight gain was lower in both males and females receiving the AA85 diet while at 15-42 d it was lower in males fed with AA85 and females fed with AA90 compared to the control diet. Feeding cost calculated based on 100 g weight gain resulted in more meaningful results than cost calculated for the production of a bird. 4. Dietary amino acid content did not significantly affect carcase, thigh (bone in and skin on) or breast meat (deboned and skin on) yields. Males fed with AA90 diet and females fed with AA90 and AA85 had lower protein contents in their breast meat (without bone and skin) compared to the ones fed with control diet.