Interactions between selected geophilic fungi (keratinofytic and keratinophylic species) and pathogenic dermatophytes were examined in dual cultures on Sabouraud glucose agar (SGA). It was demonstrated that Trichophyton mentagrophytes var. mentagrophytes together with T. mentagrophytes var., quinceanum are the species most sensitive to the influences of the geophilic fungi. Microsporum persicolor was found to be more resistant to these influences. Only a few geophilic species inhibited the growth of M. canis on SGA. Keratinophilic species, unable to initiate hair decomposition but utilize the products of this process, exerted the larger inhibitory effect on the pathogenic dermatophytes than keratinofytic fungi.