Medulloepithelioma of the optic nerve is a rare developmental tumor. We describe a 2-year-old boy with profound loss of vision associated with a visible tumor of the optic nerve head in his left eye. A clinically diagnosed retinoblastoma necessitated left eye enucleation. The histopathological diagnosis was malignant medulloepithelioma that was incompletely resected. Further tumor resection was required, and the patient received adjunctive chemotherapy and radiotherapy. Four years after treatment, the patient has neither clinical nor radiological evidence of tumor.