Fish is the best source of polyunsaturated fatty acids (PUFA), specifically n-3 fatty acids, especially eicosapentaenoic acid and docosahexaenoic acid. The objective of the present study was to determine the fat content and fatty acid compositions of 34 marine water fish species from the Mediterranean Sea. The fatty acid compositions of fish consisted of 30.10-46.88% saturated fatty acids, 11.83-38.17% monounsaturated fatty acids and 20.49-49.31% PUFA. In most species, the following fatty acids were identified: mystiric acid (C14:0, 0.72-8.09%), pentadecanoic acid (15: 0, 0.05-2.35%), palmitic acid (C16:0, 15.97-31.04%), palmitoleic acid (C16:1, 1.48-19.61%), heptadecanoic acid (C17:0, 0.31-1.84%), cis-10-heptadecenoic acid (C17:1, 0.17-2.01%), stearic acid (C18:0, 2.79-11.20%), oleic acid (C18:1n9, 2.44-28.97%), linoleic acid (C18:2n-6, 0.06-3.48%), arachidonic acid (C20:4n-6, 0.12-10.72%), cis-5,8,11,14,17-eicosapentaenoic acid (C20:5n-3, 1.94-10%) and cis-4,7,10,13,16,19-docosahexaenoic acid (C22:6n-3, 3.31-31.03%). The proportions of n-3 PUFA ranged from 12.66% for annular seabream to 36.54% for European hake, whereas the proportions of PUFA n-6 were between 1.24% for oceanic puffer and 12.76% for flathead mullet. The results of this study show that these fish species were rich in n-3 PUFA, especially, eicosapentaenoic acid and docosahexaenoic acid.