Retinopathy of prematurity is a retinal vascular disorder seen frequently in very premature infants, and is associated with poor clinical outcomes. The aim of the present study was to assess the association between the incidence of retinopathy of prematurity and mechanical ventilation, oxygen therapy, gestational age, and antenatal steroids in extremely low birth weight infants as well as to retrospectively analyze changes in the incidence and risk factors of retinopathy of prematurity over two study periods.