Frequency of Listeria monocytogenes occurrence in rainbow trout obtained from retail outlets was evaluated in this paper. Listeria spp. was isolated from all samples purchased in fish departments of local shops and 50% of isolated forms it was Listeria monocytogenes. Fish collected directly from farms, in different time periods were free from this bacterium. In „gravad” fishes inoculated with Listeria monocytogenes to the level of 100 cfu/g of raw material, maturated within 3 days at 3°C, and then stored during 4 weeks, the gradual death-rate of bacteria was observed.