Rhinocerebral mucormycosis (RCM) is an increasingly common infection in immunocompromised subjects. We report a case of RCM in an immunosuppressed gentleman known to suffer from sigmoid colon adenocarcinoma stage D and presenting with diabetic ketoacidosis, complete ptosis, and orbital cellulitis. During his hospital stay, the patient developed cranial diabetes insipidus. In spite of extensive surgical debridement and high-dose liposomal amphotericin, the disease had a fatal outcome. This case emphasizes the need for increased awareness of mucormycosis as a potentially lethal fungal infection requiring a high index of suspicion in subjects at risk. The case also illustrates a rare complication of RCM, namely diabetes insipidus.