Rhino-orbital mucormycosis (ROM) is an acute and fulminant infection. The number of ROM cases developing after coronavirus disease 2019 (COVID-19) is increasing. A 62-year-old male patient was admitted to the emergency department in northern Syria complaining of new-onset vision loss, swelling, and severe swelling of the left eye. It was noted that a 3-day course of prednisolone 250 mg was given to treat COVID-19. We found that he had a history of diabetes mellitus (DM) for 10 years. Physical examination revealed ptosis, proptosis, and ocular movement restriction in all directions in the left eye. All other systemic examinations were normal. A cranial and orbital magnetic resonance imaging scan performed after hospitalization for further evaluation and treatment showed an increase in the density of the sphenoid, ethmoid, and frontal sinus walls in the left orbit. Despite antifungal and surgical treatment, the patient died on day 14. The use of steroids in treatment and the presence of concomitant DM are the main predisposing factors. The prognosis of this disease, which has a high mortality and morbidity, is adversely affected in geographic regions where health care is inadequate.