Introduction Rhinocerebral mucormycosis is a rare disease, which causes serious and life-threatening fungal infections.The disease usually develops in immunocompromised individuals and usually begins by mimicking cellulite, especially in the face area, and shows a very rapid course. Case Report A 75-year-old male patient previously admitted to an external center with 3-4 days complaints of headache, numbness in the right half of his face and closure of his left eye was brought to our emergency department for further investigation.The cranial magnetic resonance imaging (MRI) revealed suspected opportunistic fungal infection or malignancy in the ethmoidal and sphenoidal sinuses.The patient was hospitalized with the diagnosis of opportunistic fungal infection after consultations to relevant clinics. Biopsy revealed polypes and mucocele like cystic tissues. The patient, followed-up and treated with rhinocerebral mucormicosis, was transferred to intensive care unit after deterioration of his general condition.After approximately 45 days of follow-up and treatment, the patient was lost due to multiple organ failure. Conclusion Rhinocerebral mucormycosis is an emergency that requires a multidisciplinary approach. Presence of one or more of the non-traumatic orbital apex syndrome findings should alert emergency physicians. In this and similar infections with high mortality rates, early diagnosis and treatment may lead to good results.