In this thesis the linkage between the basic chemical and fatty acid composition of trout feed and trout (Oncorhynchus mykiss) meat was investigated. A total of ten trout and belonging feed from different slovenian fish farms were collected and included in this research during spring season in 2016. The content of 52 fatty acids of feed and trout meat was determined by in-situ transesterification and capillary column gas-liquid chromatography and chemical composition according to AOAC methods. On average, 100 g of trout feed contains 7,4 g of moisture, 47,7 g of proteins, 6,09 g of ash and 21,4 g of fat. Regarding fatty acid composition 47,8 wt. % of all fatty acids belong to monounsaturated, 34,0 wt. % to polyunsaturated and 18,1 wt. % to saturated fatty acids, with PS ratio (the ratio between polyunsaturated and saturated fatty acids) 1,88, n-6/n-3 ratio 1,74, 0,80 wt. % of trans fatty acids and 3,28 wt. % of very long chain n-3 fatty acid. On average, 100 g of trout meat contains 76,1 g of moisture, 21,4 g of proteins, 1,34 g of ash and2,52 g of fat, where for fatty acid composition 42,1 wt. % belongs to monounsaturated, 38,2 wt. % to polyunsaturated and 18,9 wt. % to saturated fatty acids, with PS ratio 2,02, n-6/n-3 ratio 0,98, 0,95 wt. % of trans and 13,25 wt. % of very long chain n-3 fatty acids. Shares of α-linoleic (ALA; C18:3n-3), eicosapentaenoic acid (EPA; C20:5n-3) and docosahexaenoic acid (DHA; C22:6n-3) observed here suggest possible effect of feed (diet) source on metabolism of fat in trout meat and requires further investigation.