The authors tried in this article to review the principal aspects of deep mycoses. A special attention was paid to the clinical aspects of candidiasis, aspergillosis and cryptococcosis. The incidence of these diseases is now growing owing to the increasing use of immunosuppressives drugs and to AIDS. The difficulty of the biological diagnosis of these mycoses is discussed. Drugs currently used are amphotericin B, 5-fluoro-cytosine, ketoconazole and fluconazole. Prophylactic measures and the indications of the main drugs are considered.