Cunninghamella bertholletiae, an uncommon cause of human fungal infection, has been reported with increasing frequency in recent years in Western countries. We report a case of acute myelogenous leukemia terminated by an uncommon complication of zygomycosis caused by C. bertholletiae, which seems to be the first human case reported in Japan. In this case, the fungus disseminated many organs, including the thyroid gland.