We documented the prevalence of retinopathy of prematurity (ROP) in a group of 46 infants suffering from a moderate or severe respiratory distress syndrome and treated with surfactant replacement therapy (SRT) and 61 controls admitted in the year prior to the institution of SRT. Mortality in the treatment group was lower than in the control group (15.5% versus 23.8; P = 0.29). The ROP prevalence in the treatment group was 47.8% and in the control group 27.9%. To analyse the contribution of SRT alone to the prevalence of ROP, multivariate analysis using logistic regression technique was used. The odds ratio for SRT was 5.2 with a 95% confidence interval of 1.3-20.7, P = 0.02. The prevalence of severe ROP in the surfactant treated group was not increased compared to the control group. From our data we conclude that SRT increases the risk of developing ROP but is not associated with more severe forms of ROP.