Purpose: To determine the factors influencing the time from preterm birth and retinopathy of prematurity (ROP) detection to optimize the timing of the initial screening. Methods: This multicenter retrospective study enrolled preterm infants born before 32 weeks of gestational age (GA) and/or weighing less than 1,500 g between January 1, 2011, and December 31, 2015. ROP screening was performed using fundus photography with a wide-field camera. Population and follow-up characteristics were recorded. Results: Among the 1,266 preterm infants observed, 795 were retained for analysis. One hundred seventy-four (21.6%) cases of ROP were detected with the first examination performed at 32.3 ± 1.6 weeks of postmenstrual age (PMA) and 5.4 ± 1.0 weeks of postnatal age (PNA). The first signs of ROP were detected at 34.0 ± 1.9 weeks of PMA and 7.2 ± 1.8 weeks of PNA, respectively. In the multivariate analysis, an older GA, a longer duration of mechanical ventilation, and a lower birth weight were correlated with a longer time between preterm birth and ROP detection (p < 0.0001, p < 0.0001, and p = 0.0359, respectively). Conclusion: The first examination for ROP screening should be individualized to fit the first screening examination as closely as possible to the first signs of ROP in order to avoid unnecessary examinations without missing ROP.