The diet of large (Tl 37,3 cm) brown trout Salmo trutta m. fario L. from a beaver pond in the Bieszczady National Park was studied. The trout diet was mainly composed by Montandon’s newts Lissotriton montandoni. Fish and other vertebrates were not observed in trout’s stomach. The beavers have dammed the mountain stream and created the new habitat with stagnant water. Deep, welloxygenated beaver ponds are suitable for large fish and also for newts, during its mating season. Thus, adult newts were a prey item in the brown trout diet