The relationship between the use of indomethacin, a prostaglandin inhibitor, for closure of patent ductus arteriosus (PDA) and the occurrence of retinopathy of prematurity was investigated retrospectively. 63 preterm infants less than or equal to 1500 g who were less than or equal to 32 weeks' gestational age, appropriate weight for gestational age, with a diagnosis of PDA, and admitted during the first 24 hours of life were studied. Diagnosis of retinopathy was made by retinal examination when each infant was about 4 weeks. Diagnosis of PDA was made by clinical, radiological, and echocardiographic findings. 15 patients were treated with indomethacin because of severe congestive heart failure. There were no differences between gestational ages, birthweights, duration of oxygen therapy, or incidence of retinopathy in treated and untreated patients. We suggest that the use of indomethacin for PDA closure does not increase the incidence of retinopathy in very low birthweight infants.