Aim: To assess the effect of postnatal weight gain characteristics and multiple risk factors on treatment- required retinopathy of prematurity. Methods: The medical records of preterm infants who were followed up for retinopathy of prematurity in a tertiary referral center were retrospectively reviewed. Infants were grouped as Treatment(-) (retinal matu- ration without treatment) and Treatment(+) (treatment required). Retinopathy of prematurity findings, weight gain and weight gain rates at the 4th and 6th weeks, and clinical features were noted. The best cut-off points for the weight gain and weight gain rate were assessed with the area under the receiver operating characteristic curve. Risk factors were determined by the logistic regression model. Results: Twenty-eight of 201 preterm infants (13.5%) were in the treatment (+) group. Birth weight, ges- tational age, weight gain, and weight gain rate at the 4th and 6th weeks were lower, the duration of oxygen therapy and hospitalization was longer, and a history of bronchopulmonary dysplasia, necrotizing enterocolitis, prolonged mechanical ventilation, and erythrocyte transfusion was more common in the treatment (+) group (p<0.05). The best cut-off points (and area under the receiver operating character- istic curve) were calculated as 297.5 g (0.779) and 504.5 g (0.771) for weight gain and 21.02% (0.697) and 54.80% (0.670) for weight gain rates at the 4th and 6th weeks, respectively. History of bronchopulmonary dysplasia and prolonged mechanical ventilation were independently associated with severe retinopathy of prematurity. Conclusion: Preterm infants with a history of low weight gain profile at the 4th week, bronchopulmonary dysplasia, and prolonged mechanical ventilation should be carefully monitored for the development of the treatment-required retinopathy of prematurity.