To evaluate the association between early (within 10 d) pRBC transfusion and the development of severe ROP. This was a single-center retrospective study. Inclusion criteria were preterm infants born ≤32 weeks gestation or weighing ≤1500 g. Severe ROP was defined as infants requiring retinal laser ablation or bevacizumab injection. Logistic regression was used to identify the association between transfusions and severe ROP. A total of 1635 infants were included in the final analysis. The severe ROP incidence was 8% (126/1635). Ninety-one percent (115/126) of infants who developed severe ROP received a pRBC transfusion in the first 10 d. Early transfusion was associated with severe ROP; adjusted odds ratio of 3.8 (95% CI: 1.8-8.1). pRBC transfusions in the first 10 days of life are associated with an almost four-fold increased risk of severe ROP, independent of gestational age at birth or bronchopulmonary dysplasia (BPD) status.