Changes in lipid, protein, ash and moisture, quantitative distribution of fatty acids, cholesterol and mineral content (Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni and Zn) of six common fish species from Greece were studied. The proximate composition of all samples was significantly influenced by the fishing period, even the cultured ones. The sum of C20:5ω-3 and C22:6ω-3 ranged from 1.18 to 2.76 for sardine, from 0.37 to 1.99 for bogue, from 1.1 to 1.52 for mackerel, from 1.23 to 1.46 for sea bass, from 1.00 to 1.24 for trout and from 0.26 to 0.45 g/100 g edible portion for hake samples. Besides the ratio of ω-3/ω-6 polyunsaturated fatty acids ranged from 6.80 to 19.00 for the wild fish samples and from 1.01 to 3.67 for the cultured ones. Cholesterol of sardine, bogue, mackerel, trout and sea bass ranged from 37 up to 76 mg/100 g edible flesh, while it was varied from 72 to 124 mg/100 g in the flesh of hake. The concentration of minerals was detected at acceptable levels. All fish samples seemed to be quite good sources of Mg, Zn and Fe. Co was not detected in the samples studied.