Mucormycosis is a disease caused by fungi of the Mucorales family, widespread in the environment, with pronounced angiotropism and the ability to angioinvasion, leading to thrombosis with surrounding necrosis. The main triggers for the development of mucormycosis are: immunodeficiency states, use of glucocorticosteroid drugs, decompensation of diabetes mellitus, concomitant diseases, age > 65 years. We present a clinical case of rhinocerebral mucormycosis in a 79-year-old patient against the background of uncontrolled type 2 diabetes mellitus with ketoacidosis, a condition after previous glucocorticosteroid therapy for COVID-19 (according to the severity of the disease). After suffering a new coronavirus infection caused by the SARS-CoV-2 virus, she was admitted to the hospital with complaints characteristic of mucormycosis. On the 5^th day of hospital stay, the patient’s condition worsened significantly, despite the correction of the therapy, and on the 12^th day the patient died. According to the results of the autopsy, it was established that the rhinocerebral mucormycosis was complicated by thrombosis of the anterior and posterior left cerebral arteries with subsequent infarctions in the frontal lobe and parieto-occipital region of the brain left hemisphere, cerebral edema, which was the immediate cause of death.