Introduction: Given the advances in neonatology have increased survival of premature infants, an increase in transfusions and thus their effects. Materials and Methods: Cross-sectional observational study. We included neonates transfused with 2 red blood units in infants of Popayan for a year. We register demographic data, laboratory and hemodynamic before, during and in the first 24 hours post transfusion and adverse reactions. Results: The prevalence of transfusion was 17.3%. 50% were children, the average age at which transfusion was performed was 22 days, the average weight was 1350 g., Mean gestational age 30 weeks, 71% of the children had sepsis. 96.8% had a transfusion event, 85.5% had adverse reactions: metabolic rate 45.1% and 21% overload. Considering the attribution definite reaction was determined by 35.5%. Significant association was found (p <0.05) adverse reaction with sepsis and comorbidities present up to four. There was also statistically significant association between volume overload and female, preterm and sepsis. There were more metabolic reactions in preterm infants with asphyxia. Conclusion: In high prevalence of transfusion reactions and events in these units, it is recommended to minimize blood sampling and evaluate risks versus benefits before deciding a transfusion.