The increase of dermathophytosis in patients with poor therapeutic response leads us to study the antifungal susceptibility of 36 clinical isolates to itraconazole, ketoconazole and fluconazole by the E-test method. According to established parameters by the Clinical Laboratory Standards Institute, the resistance to one or more antifungal drugs was demonstrated in seven isolates (19.4%) as follows: three Trichophyton rubrum, three T. mentagrophytes and one T. tonsurans. A T. rubrum isolate was resistant to the three azolic drugs; the other six only to fluconazole. It is important to establish the antifungal susceptibility as part of the study procedures in patients with dermatophytosis and a poor antifungal response.