Seasonal variations in rainbow trout were studied in four geographically different places of growth. Experiments were carried out in May, July, September and February. The fish was weighed and tested for approximate chemical composition, total and coliform bacteria, and organoleptic quality. Besides chemical and microbiological analyses, tests were made from the cultivating waters. The results indicated that the fish varied according to the season and place of growth. In chemical analyses the greatest differences occurred in the amounts of water and fat. The organoleptic quality of trout seemed, however, to be mostly influenced by the places of growth.