Seasonal variations in the fatty acid compositions of red mullet (Mullus barbatus) captured from Iskenderun bay, northeastern Mediterranean, were investigated. In all sampling seasons, the major fatty acids of red mullet were palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), palmitoleic acid (16:1), eicosapentaenoic acid (EPA, 20:5ω3) and docosahexaenoic acid (DHA, 22:6ω3). The fatty acid contents of red mullet were influenced by seasonality. The levels of polyunsaturated fatty acid were 17.32% in autumn, 17.69% in winter and 20.13% in spring. The levels of DHA in the total fatty acids in autumn, winter and spring were 4.36, 8.25 and 10.89%, while those of EPA were 7.93, 4.59 and 4.56, respectively. The present study suggest that red mullet is a good source of ω3 series fatty acids, and the weekly consumption of 300 g of red mullet in autumn, winter or summer could meet EPA + DHA requirements of people. PRACTICAL APPLICATIONS Red mullet is one of the most commercially important fish species in many Mediterranean countries. Little information is available on the fatty acid composition of red mullet. Therefore, seasonal proximate analysis and the fatty acid composition of red mullet were determined and discussed in this paper. There is much interest in the beneficial effects on human health that is related to consumption of marine lipids. Determination of the effects of different fishing seasons on the fatty acid composition of red mullet will provide valuable information concerning the nutrient value of this seafood for both consumers and the researchers working on nutrient tables. In addition, this basic information will be obtained for the fish processing industry.