PURPOSE: To report a series of 13 immunocompetent patients who developed new-onset uncontrolled diabetes mellitus (DM) following COVID-19 infection and presented as rhino-orbital mucormycosis (ROM). METHOD: Retrospective study. RESULTS: A total of 127 patients of COVID-19 Associated Mucormycosis (CAM) were evaluated at four centres in India. All patients underwent endoscopic sinus debridement surgery and received systemic amphotericin-B therapy. Five patients (5/13; 38.4%) received retrobulbar amphotericin-B injections. Orbital exenteration was performed in advanced orbital involvement or progression of orbital disease in spite of maximal medical therapy. In his cohort, 13/127 (10.2%) patients presented with new onset DM, where one patient had bilateral disease. The mean age was 35.9 years (range: 20-51 years) and the mean duration from diagnosis of COVID-19 to the diagnosis of mucormycosis was 14.2 days. While 7/13 (53.8%) of the patients received systemic corticosteroids during the course of their treatment for COVID-19, six patients received no steroids or immunomodulators. The mean follow-up period was 9.2 weeks (range: 3-18 weeks) following discharge. Life salvage was possible in 100% of the cases. While overall globe salvage was possible in 42.8% (6/14 eyes), the globe could be preserved in 4/5 patients who received retrobulbar amphotericin-B injections. CONCLUSIONS: Those involved in the care of COVID-19 patients should be aware about the possibility of recent-onset DM, even in patients without a history of corticosteroid therapy. Rarely, recent-onset DM following COVID-19 may present as rhino-orbital mucormycosis, which requires aggressive surgical and medical intervention.