The diet of the otter (Lutra lutra L.) was assessed through spraint analysis at three different streams in the Beskydy Mountains (north-east Czech Republic) and compared with fish availability and river management procedures. The remains of 3 478 prey items were recorded in 894 spraints, collected between May 2000 and May 2002. Fish were the dominant species taken (90%), followed by amphibians (50%). The most frequently occurring species of fish were the Carpathian sculpin Cottus poecilopus (71%) and brown trout Salmo trutta m. fario (65%). The composition of the otter’s diet tended to reflect the fish availability (biomass) in streams. Despite the general similarity of the different streams studied, diet composition differed significantly. The differences in diet could be explained by differences in fishery management (stocking) together with the location of migration barriers.