Sardine (Sardina pilchardus Walb.) is an important Mediterranean commercial fish species. In this study, the lipids of sardine filets, fished in the Adriatic Sea at different times, were examined. In function of their total lipid (TL) content, sardine filet samples were grouped into lean (TL < 4%) and fat (TL > 4%). It was demonstrated that the differences of TL were exclusively due to a seasonal cyclical increase of neutral lipids. In fact, during moderate-hot months, sardines accumulated reserve fat that was metabolised during the winter months. The fatty acid composition was similar in both sardine sample groups and the fatty acid profile was equally distributed among saturated fatty acids, on average 38.3%, 31.2% monounsaturated, and 30.4% polyunsaturated. The polyunsaturated fatty acid n3 (PUFA-n3) represented on average 20.9%, always higher than PUFA-n6. C20:5n3 eicosapentaenoic acid, (EPA) and C22:6n3 docosahexaenoic acid (DHA) were the must abundant PUFA-n3. Under nutritional aspects, the lipids of 100 g of fat-sardines provided PUFA-n3 quantities, in particular EPA and DHA, significantly higher than human daily requirements. In lean-sardines, the PUFA-n3 input drastically decreased and was estimated that EPA and DRA inputs in 100 g of sardines covered around 17% and 50% of daily requirements, respectively. Finally, cholesterol was equal to 93 mg/100 g of sardines, ranging from 67 to 131 and it did not increase in relation to the total lipid content. In conclusion, this study has highlighted that, under nutritional aspects, regarding EPA and DHA inputs, it is preferable to consume sardines with at least 4% total lipids.