PURPOSE: Retinopathy of prematurity (ROP) is a visual-impairing disorder of the developing retinal vasculature in premature infants. Recent advances in neonatal care have led to an increase in the vulnerable premature population. The aim of this retrospective study was to assess the incidence of ROP and its risk factors according to degree of prematurity.METHODS: Data from a sequence of 1,562 infants <32 weeks of gestational age, admitted to the Jewish General Hospital Neonatal Intensive Care Unit, a tertiary care perinatal center in Montreal, Canada, were reviewed to determine the incidence and risk factors of ROP. Perinatal risk factors for ROP were analyzed using univariate and multivariate analyses in four consecutive gestational age (GA) groups (24-25weeks, 26-27 weeks, 28-29 weeks and 30-31 weeks).RESULTS: The overall incidence in our study was 15.6 %. Severe ROP, defined as stage 3 or plus disease was detected in 5.2 % of the neonates screened. In the univariate analyses, many risk factors in each GA group were found to have a significant association with ROP. On subsequent multivariate logistic regression analysis, birth weight, small for gestational age, the presence of patent ductus arteriosus (PDA), sepsis, necrotizing enterocolitis (NEC), and mechanical ventilation >7 days were independently associated with the development of ROP. Birth weight was consistently an independent risk factor for ROP in all GA groups.CONCLUSION: Our study confirmed the importance of birth weight as an independent ROP risk factor. Sepsis, NEC, PDA, and prolonged mechanical ventilation have been shown to be independent risk factors in the different gestational age groups. Hippokratia 2016, 20(2): 121-126.