In the Republic of Belarus, one representative of the genus Corynosoma - C. strumosum (Rudolphi, 1802) that is a causative agent of corynosomosis and that is of medical value is parasitic on animals. In Belarus, this proboscis worm has been encountered only in European and American minks. The author of the paper found this helminth in 2 of the 50 examined American minks in Byelorussian Polesye in 1980-2001. In this region, there were no C. strumosum larvae in fishes (1394 fishes of 21 species were studied). It is noted that the American mink plays a dominant role in the circulation of invasion and the attention of medical workers ofBelarus is drawn to the existing risk of human infection with the pathogen of Corynosomosis.