Rhino-cerebral zygomycosis (RCZ) is an acute rapidly progressive fungal infection usually occurring in patients with diabetes mellitus and ketoacidosis. Patients typically complain of pain located in the facial, nasal or orbital regions, followed by sudden blindness and cranial nerve palsy. Early diagnosis, correction of risk factors, prompt surgical removal and aggressive antifungal therapy are warranted as life-saving treatments. The following report describes a case of a lethal RCZ which occurred in an apparently healthy woman with latent non-decompensated diabetes mellitus and a fetal-type posterior (FTP) circle of Willis.