Introduction: Mucormycosis is an aggressive infection that can cause significant disease in immunocompromised patients. Case presentation: A case of a diabetic patient who developed rhinocerebral mucormycosis while receiving consolidation chemotherapy for leukaemia is described. Conclusion: Rhizopus oryzae was identified in tissue biopsies by pan‐fungal PCR and DNA sequencing, which provided the only means to identify the pathogen.