This study was aimed to investigate the influence of age and sex on minerals content and fatty acids profile of Nile Tilapia (Oreochromis niloticus) fillet. Samples were cool transported from Lake Zeway to Food Science and Nutrition laboratory of Addis Ababa University. Minerals content were analyzed using Flame Atomic Absorption spectrophotometer and Fatty acid profile was determined using gas chromatography. Female fish contained significantly (p<0.05) higher calcium and phosphorus as compared to male. Calcium and zinc significantly (p<0.05) decreased as age of fish increased but phosphorus significantly (p<0.05) increased with increase in age of the fish. Sex had no significant effect (p>0.05) on Iron and Zinc content. Monounsaturated fatty acids constituted the largest proportion of total unsaturated fatty acids in both sexes. Oleic acid was relatively higher in female than male. Conversely, the polyunsaturated fatty acids were higher in male as compared to female.