ABSTRACT: In fish processing, viscera are generally considered waste products and often discarded. Our research objective was to use Atlantic salmon (Salmo salar L.) viscera as a source of fish oil and to increase its concentration of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) by lipase-assisted hydrolysis. Lipids from fillets and viscera had similar fatty acid compositions. After the enzymatic hydrolysis, acylglycerols were isolated from free fatty acids, therefore increasing the concentrations of EPA and DHA in the acylglycerols. Among the 6 commercial lipases investigated, lipases from Pseudomonas cepacia and Candida rugosa were the most effective following incubation of viscera oil at 35 °C for 20 h. Salmon viscera were a good source for fish oil, and the concentration of DHA and EPA was doubled by using microbial lipases.