Background/aim: This study aimed to compare the incidence of any stage of retinopathy of prematurity (ROP) and type 1 ROP between extremely preterm multiple- and single-birth infants. Materials and methods: In this retrospective study, we included extremely preterm infants who were ≤27 weeks of gestational age at birth. The screened infants were divided into two groups: single and multiple births. The incidence of any stage of ROP and type 1 ROP was compared between the groups. Results: This study included 301 infants; 225 were in the single-birth group and 76 were in multiple-birth group. The incidences of any stage of ROP and type 1 ROP among all infants were 70.7% (213 of 301) and 16.6% (50 of 301), respectively. Regression analysis showed that lower birth weight (OR = 0.99, P = 0.004) and longer length of stay in hospital (OR = 1.02, P = 0.002) were significantly correlated with any stage of ROP. Compared to single-birth infants, the risk of any stage of ROP and type 1 ROP did not statistically increase for multiple-birth infants (P > 0.05). Conclusion: This study showed that multiple birth had no significant correlation with ROP development in extremely preterm infants.