Perioperative transfusion has adverse effects in patients undergoing cardiac surgery. The effect of leukocyte-depleted (LD) erythrocyte transfusion in pediatrics’ cardiac surgery was until now unknown. A retrospective cohort study was conducted among pediatric patients who were no more than 3 years old and transfused with red blood cells during an open-heart surgery. Investigations were made into mechanical ventilator treatment duration, length of stay in the intensive care unit (ICU) and 90-day survival. A total of 174 pediatric patients were included in our study. The average age was 21.90 months old and the average weight was 9.18 kg. There were 107 patients received non-leukocyte-depleted (NLD) red blood cell (RBC) transfusion and 67 patients received LD erythrocyte transfusion. No statistically significant differences were detected in the 90-day survival rates between the NLD group and the LD group. Statistically significant differences were detected in the time spent on the mechanical ventilator[(5.3 ± 2.0) d vs
. (2.6 ± 1.0) d; P= 0.01] and the lengths of ICU stay [(9.4 ± 6.0) d vs
. (5.6 ± 4.0) d; P=0.02] between the NLD group and the LD group. LD blood transfusion was associated with decreased length of stay in ICU and the decreased time on the mechanical ventilator in pediatric cardiac surgery.