Rhino-orbital-cerebral (ROC) mucormycosis is an uncommon, acute and aggressive fungal infection. It remains a challenging problem to clinicians despite aggressive debridement surgery and antifungal therapy. The authors describe a case of ROC mucormycosis with pericranial abscess occurring in a female patient with uncontrolled diabetes mellitus. The infection initially developed in the right-sided nasal sinus and later progressed through the paranasal sinuses with the invasion of the peri-orbital and frontotemporal region, due to the delayed diagnosis and treatment. Numerous non-septate hyphae of the zygomycetes were identified by a punch biopsy from the nasal cavity and by an open biopsy of the involved dura. The patient was treated successfully with extensive debridement of her necrotic skull and surrounding tissues, drainage of her pericranial abscess and antifungal therapy, including intravenous amphotericin B for 61 days and oral posaconazole for the following 26 days. She returned to a normal life and has had no recurrence since the end of her treatment 15 months ago.