Reported is a child who at the age of 18 months had presented with a left retinoblastoma. The lesion had involved the optic nerve (Stage IV), and was successfully treated by enucleation and radiotherapy. The radiation field did not include the mandible or the submandibular triangle. He was followed up until he left the area aged 11 years. He represented aged 12 years with a progressive swelling of the left submandibular gland. Histology of the surgically excised submandibular gland revealed a mucoepidermoid carcinoma of the submandibular gland. This case highlights the need for continual surveillance in survivors of retinoblastoma, as second primary tumours occur both within and outside of previous radiation fields. The clinical association between retinoblastoma and mucoepidermoid carcinoma of the submandibular gland has not been previously reported.