A 2,948-g full-term male infant, the product of an uncomplicated pregnancy, developed fundus changes consistent with retrolental fibroplasia in the absence of supplemental oxygen therapy. He had no associated illnesses or congenital anomalies, and had not received exchange transfusions. There was no family history of ocular disease. Changes similar to those of retrolental fibroplasia do occasionally occur in fullterm infants who have had no supplemental oxygen therapy. A relative hyperoxia caused by the increase in arterial oxygen saturation occurring at birth is one possible explanation for these events. This rise, plus susceptibility factors apart from prematurity, may account for these unusual cases. Additionally, these cases may represent sporadic examples of familial exudative vitreoretinopathy.