Mucormycosis is a progressive and life-threatening disease that has been increasingly reported in patients infected by coronavirus diseases 2019 (COVID-19). We describe a case of rhino-orbital mucormycosis with central nervous system involvement resulting in bilateral blindness and intracranial extension in a patient with uncontrolled diabetes mellitus (DM) and mild COVID-19 infection. A 35-year-old obese male, recently diagnosed with DM, presented to the emergency department suffering from dizziness, headache, speech difficulty, and facial weakness. His glycosylated hemoglobin was 10.4% and his reverse transcriptase–polymerase chain reaction (PCR) test came positive for COVID-19. Ocular examination revealed left eye proptosis, ophthalmoplegia, and lid edema with no ocular movement. Imaging studies showed pansinusitis and periorbital and orbital cellulitis with intracranial involvement. Histopathology and biopsy examination confirmed mucormycosis. Medical management included glucose control and liposomal amphotericin B therapy. Septoplasty and functional endoscopic sinus surgery was performed as emergency procedures. The patient survived with bilateral blindness. In this case, we described the importance of considering mucormycosis in COVID-19 patients with uncontrolled diabetes, particularly those presenting with sinusitis, headache, and orbital edema symptoms. Despite intensive antifungal therapy and surgical intervention, it is a serious opportunistic fungal infection associated with long-term complications.