The frequency of secondary infections has also increased following the ongoing coronavirus pandemic. We aimed to attract attention to the COVID-19-related mucormycosis, a highly mortal complication of COVID-19, and its treatment. A retrospective review of the patient database was performed after the pandemic declaration. These patients’ medical files, treatment charts, and radiological and histological data were examined. The study group consisted of three COVID-19-related mucormycosis patients. All three patients had uncontrolled diabetes. One patient had no previously diagnosed diabetes and died due to widespread mucor infection and severe ketoacidosis. In the other two patients, the diagnosis was made promptly by frozen examination, endoscopic debridement was performed, antifungal treatment was started immediately, and infection was controlled following strict blood sugar control. The widespread use of steroids, and uncontrolled diabetes, are major risk factors that make patients susceptible to mucormycosis. In patients with COVID-19, physicians should be cautious of the possibility of invasive fungal infection. In addition to debridement, an active interdisciplinary approach can help reduce mortality