INTRODUCTION: Retinopathy of prematurity (ROP) is one of the main reasons of preventable childhood blindness. In the development of ROP, MicroRNAs may be effective in the balance of factors that inhibit and activate angiogenic factors. We aimed to determine the changes in the blood levels of miR-146a, miR-143, miR-210, miR-21, miR-126, miR-211, miR-221, miR-106 and let 7f and to investigate their association with ROP. We hypothesed that the level of these miRNAs changed significantly in ROP cases. MATERIALS AND METHODS: This observational study was conducted prospectively in preterm infants with ROP. Serum levels of 8 miRNAs were measured. The relationship between disease stage and progression with miRNA gene expression was analysed. Preterm infants without ROP were taken as the control group. RESULTS:47 patients with ROP and 14 controls, were included in the study. In the ROP group, miR-210, miR-146a, miR-21 were statistically significantly lower. In the ROP group the expression level of miR-143 was insignificantly lower, miRNA-221 was insignificantly higher, and miR-106, miR-126 and let 7f were variable. CONCLUSION: It was observed that miR-210, miR-146a, miR-21 and miR-143 were significantly lower in patients with ROP compared to the control group. However, no association could be established between the type of miRNA and stage of ROP. These miRNAs may be used as adjunctive biomarkers for diagnosis of ROP.