Tests for myococarriers were made on 4.297 wild small mammals. Clinical examinations only were carried out on 1,204 animals, both clinical and laboratory examinations on 3,093 animals. The suppurative form of trichophytosis was diagnosed in only one specimen of Microtus oeconomus out of 1,204 animals examined. T. ectothrix microides was found in the hair taken from the focus. T. mentagrophytes var. gypseum was obtained by culture on nutrient media. No clinical signs of mycosis were found in 3,093 animals, but seeding of the hair 175 animals (5.65%) on Sabouraud's agar with chlortetracycline and acti-dione produced cultures of T. mentagrophytes var. gypseum. The fungus was most frequently isolated in clinically healthy water rats, common field voles and field mice (Arvicola terrestris, Microtus arvalis, Apodemus agrarius). Mycocarriers were most frequently found among small mammals living in corn fields (5.9%), less frequently in water meadows (0.9) and sporadically in forests and bushes (0.1%). The possibility of bringing mycocarriers from the fields into inhabited areas during the transport of forage was reported.