Mucormycosis with hemipansinusitis and left orbital involvement was observed in a 66-year-old diabetic woman. Diagnosis was confirmed by mycology and pathology examinations. The patient was treated surgically with wide exeresis of necrotic tissue and medically with amphotericin B and insulin. Cure was obtained after three months of treatment at the cost of retraction of the left nostril due to infectious lysis and resection of the nasal infrastructure. The sinus involvement was exceptional compared with reports in the literature. Mucormycosis is an uncommon condition caused by opportunistic infection in immunodepressed subjects. The causal agent is a fungus belonging to the Rhizopus, Absidia or Mucor genera. Prognosis is poor with overall mortality reaching 50%.