The fatty acid (FA composition of raw, salted, and fermented fish products prepared from two populations of Baikal omul ( was determined. Total lipid content in the raw, salted, and fermented fish products was 3.85, 4.04, and 3.76%, respectively. Overall, the most abundant fatty acids were 14:0 (myristic acid, 16:0 (palmitic acid, 16:1n-7 (palmitoleic acid, 18:1n-9 (oleic acid, 20:5n-3 (eicosapentaenoic acid, and 22:6n-3 (docosahexaenoic acid, DHA. Polyunsaturated FAs were the main fatty acid group. Among unsaturated FA, n-3 forms dominated. The highest amounts of n-3 FAs were found in raw fish, followed by fermented and salted fish. Salting significantly increased the content of some FAs (15:0, 16:2n-4, 18:3n-3, 20:3n-3 compared with raw fish and decreased the DHA content. The FA... composition of fermented fish did not differ from that of raw fish. The n-3:n-6 ratio did not differ between raw, salted, and fermented fish from population A, while the ratio was higher in raw fish from population B. Overall, thiobarbituric acid reactive substances, and thereby oxidation, were significantly lower in raw fish than in salted and fermented fish. Salting, but not fermentation, affected the FA composition of fish.