Objective To investigate the predictive effect of neutrophil/albumin (N/A) on extubation in pediatric patients undergoing cardiopulmonary bypass (CPB) cardiac surgery for congenital heart disease. Methods A retrospective cohort study of 72 pediatric patients who underwent CPB surgery from January 2017 to May 2019 was conducted. The demographic data ［gender, age, height, weight, BMI, clinical diagnosis, ASA classification, cross‑clamp time, CPB time, operation time, postoperative extubation time, postoperative duration of intensive care unit (ICU) stay and postoperative length of hospital stay］ and preoperative (1 day before operation) and postoperative (1 day after operation) levels of neutrophil and albumin of the pediatric patients were collected. N/A was calculated based on the data and perioperative changes in N/A were analyzed. Spearman rank correlation coefficients were used to analyze the influencing factors of postoperative albumin level and N/A. Receiver operating characteristic (ROC) curve was applied to analyze the prognostic value of postoperative N/A on early extubation. Results Compared with preoperative, postoperative neutrophil counts and N/A were significantly increased (P<0.05), while albumin levels were decreased (P<0.05). Postoperative N/A was significantly correlated with extubation time (P<0.05). There was no correlation between the age, BMI, ASA classification, CPB time, cross‑clamp time, operation time with postoperative N/A (P>0.05). Postoperative albumin levels were associated with age, CPB time, cross‑clamp time, and extubation time (P<0.05), but not with BMI, ASA classification, and operation time (P>0.05). The area under the receiver operating characteristic curve (AUC) of postoperative N/A for predicting early extubation failure was 0.837. The sensitivity and specificity were 78.3% and 79.6%. Conclusions Postoperative N/A might be a valuable predictor for extubation in pediatric patients undergoing CPB.