ABSTRACT. The aim of this study was to evaluate the inclusion of soybean oil in the diet of female silver catfish (Rhamdia quelen) and its effect on the growth, composition, lipid profile and fillet acceptability thereof. In this experiment, 144 fish (237.75 ± 22.35 g) were distributed among 18 tanks (280 L) for 80 days. The use of 10% soybean oil in the fishes’ diet promoted higher weights (373.82 g) and better feed conversión ratios (1.5) for female silver catfish. The soybean oil levels tested did not interfere with fillet acceptability. Increasing soybean oil in the diet increased the quantity of unsaturated fatty acids in the fillets, which enhanced their nutritional quality. The use of 10% soybean oil is recommended for the female silver catfish diet.