Dermatomycoses are the most common form of mycoses, which include superficial infections of the skin, particularly the epidermis, human hair and nails, and animal hair, horns, claws and hooves. Once the etiological agent is identified as keratinolytic filamentous fungus classified as a dermatophyte, the infection is diagnosed as dermatophytosis, also known as ringworm or tinea. These fungi are cosmopolitan pathogens found in many ecological niches such as soil human and animal keratin tissues. This article describes the synthetic clinical picture of infections and the results of research related to the treatment of dermatophytoses caused by Microsporum canis in cats. The frequency of isolation of this pathogen from skin lesions is usually higher in cats than in dogs, and more than 90% of dermatophytic lesions in cats and 75% in dogs are etiologically related to this species. A critical factor in the spread of M. canis is the asymptomatic carriage, which is an increasingly common phenomenon in the cat population. Research conducted in recent years shows that up to 50% of people who come into contact with carriers are symptomatically infected. In addition, about 40% of patients with zoonotic infections with the M. canis experience treatment failures and relapses due to drug resistance, premature discontinuation of therapy by the patient, lack of penetration of the drug into the tissues, or its variable bioavailability.