The occurrence of retinoblastoma in an eye with persistent hyperplastic primary vitreous (PHPV) is reported. These are both rare lesions. The absence of previous reports of their association has led to the clinical impression that the occurrence of PHPV in a microphthalmic eye precludes the presence of retinoblastoma. The coexistence of these lesions in the present case may represent a coincidence. Their occurrence in the same eye is felt to be noteworthy, nontheless, because of its clinical implications and the possibility of a common underlying etiology.