We administered miconazole to patients with deep-seated fungal infections, to investigate into the clinical and mycological responses to the drug and also into its clinical safety. We also looked into the responses of amphotericin B (AMPH), flucytosine (5-FC) and the combination of the 2 drugs to deep mycoses in the past 10 years, for retrospective comparison of the findings achieved in the treatment with miconazole. A clinical response rate of 85% (29/34 patients) was achieved in the treatment of deep-seated fungal infections with miconazole. Mycologically, a fungus eradication rate of 79% (22/28 patients) and a fungus decrease rate of 11% (3/28) were achieved with the miconazole treatment, comparison of the response to miconazole alone and that to AMPH alone revealed that the former was significantly preferable. Side effects of miconazole were observed in 23% of the treated patients (15/66). Statistical analysis of the incidence of side effects of miconazole and that of AMPH showed that the former was significantly lower.