Continuous awareness of systemic mycosis in immunocompromised patients is important. Early diagnosis is based on (direct) histologal examination and CT scan. Since treatment should start as early as possible, there is usually no time to await results of tissue cultures. Systemic treatment with amphotericin B and aggressive surgical débridement should be performed as soon as possible, while the place of hyperbaric oxygen and G-CSF remains to be established. In addition to routine preventive measures, prophylactic intranasal application of amphotericin B seems to be of value.