Salmonelloses belong to the most important alimentary diseases. From 1989 the main source of infection is S. Enteritidis (95% and more). The ratio of S. Typhimurium in the etiology declined gradually since 1994 from 3% in 1993 to 1.9% in 2001. The number of detected multiresistant strains STM DT104 is so far low in the Czech Republic. In 2000 laboratory tests confirmed 53 and in 2001 a total of 63 strains. Analysis of these strains revealed: 1. the proportion of multiresistant strains STM DT104 of the total number of isolated STM strains increased from 7% in 2000 to 11.5% in 2001, 2. the territory in the CR where these multiresistant strains were found expanded, 3. the relationship of proportions of the most frequently detected STM phagotypes in the human population changes: in 2000 this ratio was balanced, in 2001 the ratio of phagotype DT104 is roughly three times higher than of DT 141, 4. analysis of all STM strains from the environment and animals indicates that the frequency of STM DT104 is 73%. Almost 90% of these strains are multiresistant (resistant to one or several antimicrobial substances). The highest number was found in calves, piglets but also in poultry.With regard to the results of the submitted work it is important to concentrate attention on detection and further laboratory examination of STM strains in the human and animal population.

        Key words: S. Typhimurium – STM DT104 – multiresistance.