Abstract: Objective:To investigate the incidence of retinopathy of prematurity (ROP) in the premature infants less than 34 weeks' gestation in 25 neonatal intensive care units (NICU) in China. Methods:The data were from the clinical database of preterm infants established by a cluster randomized control study of "REduction of Infection in Neonatal intensive care units using the Evidencebased Practice for Improving Quality (REINEPIQ)" . All preterm infants with less than 34 weeks' gestation who received at least one ROP screening during hospitalization in 25 tertiary Chinese NICUs from May 2015 to April 2018 were enrolled. Results:A total of 14, 015 preterm infants <34 weeks' gestation received ROP screening during hospitalization during the study period. Overall 2, 304 infants (16.4%) were diagnosed with ROP. Incidence of stage 1, stage 2 and stage 3 or above were 7.8%, 7.2% and 1.5%, respectively. Among infants with gestational age <28 weeks, the incidence of ROP and stage 3 or above ROP were 56.5% and 9.6%, respectively. Among infants with birth weight <1, 000 g, the incidence of ROP and stage 3 or above ROP were 54.2% and 9.6%, respectively. Among infants with birth weight from 1, 000 g to 1, 499 g, the incidence of ROP and stage 3 or above were 22.1% and 1.5%, respectively. Among all infants with ROP, 8.2% (188) received treatment with 62% (117) receiving intraocular medicine injection. Significant variations of ROP incidence existed among the included NICUs. Conclusion:The incidence of ROP among infants <34 weeks' gestation was 16.4% in 25 tertiary Chinese NICUs with relatively high proportion of treatment and significant variations among different NICUs.