Zygomycoses are severe angio-invasive fungal infections that develop in immunocompromised and diabetic patients. Any episode of sinusitis not responding to short-term antibacterial therapy should evoke the diagnosis of zygomycosis in the latter population, especially in cases of a surrounding necrotic area. Appropriate diagnosis is obtained after careful direct examination of the sample and culture. Current therapy underscores the need to control glycaemia and acidosis in addition to the need for urgent administration of high-dose liposomal amphotericin B in combination with extensive surgery.