Freshwater fish production and consumption have increased in Brazil in recent years, especially Nile tilapia (Oreochromis niloticus). Tilapia has white meat, firm texture and lack of spine "Y", characteristics that favor its consumption. The objective of this study was to evaluate the fatty acid profile of O. niloticus fed with different levels of protein and digestible energy. The experiment was carried out at the Federal University of Paraná for 96 days. Twenty rations with five levels of digestible protein (DP) were formulated: 14, 19, 24, 29 and 34% and four of digestible energy (DE): 2,600, 2,800, 3,000 and 3,200 Kcal/kg. A total of 360 Nile tilapia distributed in 60 plastic boxes (1,000/L) were used. The animals were fed at 8:00 a.m., 1:00 p.m. and 5:00 p.m. At the end of the experimental period the animals were slaughtered in cold water (1°C), then stored in hermetically sealed plastic bags until analysis of the fatty acid profile. There were no significant interactions (P > 0.05) for DP x DE. Among the saturated fatty acids, palmitic acid was obtained in a higher concentration (15.84%) in all treatments. For the unsaturated fatty acids, the highest concentration found were oleic (18.86%) and linoleic (8.1%). The fatty acid composition of the carcasses reflected the lipid composition of the soybean oil, used as dietary energy source, whose predominant fatty acids are linoleic (55.1%), oleic (21.5%) and palmitic (12%). Unsaturated fatty acids are dispensable for Nile tilapia in the diet, however, the greater amount of these fatty acids would increase their popularity among the consumers, because of the benefits against cardiovascular and inflammatory diseases. Based on the results obtained we concluded that the different diets based on soybean and corn meal did not affect the fatty acid profile in the Nile tilapia carcass.