Cerebral angioinvasion is a fatal complication of disseminated aspergillosis and has been rarely described in diabetic population in the absence of ketoacidosis. We present a case of invasive fungal sinusitis in a 79 year old diabetic man who presented with chronic frontal headaches. Despite appropriate medical and surgical treatment, the disease progressed and the patient eventually succumbed to a fatal ruptured mycotic aneurysm. We emphasize that clinicians should consider this in the differential diagnoses of all diabetics who present with chronic sinusitis, as early diagnosis could be the key in the successful treatment.