Effects of interaction of season, sex and size on nutrient composition and fatty acid profiles of freshwater crayfish (Astacus leptodactylus) caught from the Egirdir Lake were investigated on a factorial level. In the factorial analysis; 4 levels of season factors (autumn, winter, spring, summer), 2 levels of sex factor (male, female) and 1 level size factor were available. According to the results of biochemical analysis, effects of seasons were determined on crude protein and moisture levels. Crude ash levels changed depending on sex and season. There were no interactions of these three factors on the crude fat levels. The season and sex affected on LA, alpha-LNA and Sigma HUFA levels. ARA, EPA, DHA, Sigma SFA and Sigma PUFA levels were affected from seasonal changes. Interaction of season/sex affected to Sigma MUFA levels. The crude protein content, DHA, EPA and n-3 contents in tail muscle of A. leptodactylus increased by feeding in summer while these contents decreased by gonadal development in autumn. Therefore, in terms of nutritional protein contents, EPA, DHA and n-3 of this species were higher in summer. EPA, n-3 and DHA contents are important for A. leptodactylus.