Mucormycosis is fulminant fungal infection that usually occurs in debilitated patients with an underlying pathologic condition. The common clinical types include rhinocerebral, pulmonary, disseminated, and intestinal forms. This report describes 11 cases seen in our institution since 1970. Of nine patients with underlying diabetes mellitus, eight developed rhinocerebral mucormycosis and one had the cutaneous form. Two additional patients with acute leukemia showed the disseminated and pulmonary forms of mucormycosis. In nine patients, the diagnosis was established by histologic appearance and by culture of infected tissue obtained by biopsy. In two patients the diagnosis was made during postmortem examination. Five patients survived. We have emphasized the importance of early diagnosis and prompt, appropriate medical and surgical therapy to obtain a significant survival rate in patients with this frequently fatal disease.