Background: The use of NT-proBNP in predicting outcomes after juvenile congenital heart surgery is uncertain. Objective: We wanted to determine whether the novel biomarker NT-proBNP might be used to identify babies at increased risk of readmission or death after congenital heart surgery. Patients and Methods: This was a cross-sectional study done from April 2021 to January 2022, at Pediatric Intensive Care Units at Alhusien and Bab Alsharia University Hospitals. Our study included 100 patients in the pediatric and adolescent age group. Biomarkers were assessed using an enzyme-linked immunosorbent assay with patterned arrays and electrochemiluminescence detection. The manufacturer's specifications were respected while repurposing pre-owned kits and equipment. Results: Soluble suppression of tumorigenicity 2 pre and postoperative values were significantly associated with readmission. Postoperative NT-ProBNP values were significantly associated with readmission. Only preoperative soluble suppression of tumorigenicity 2 with cut-off value of 1.46 showed significant association with readmission with sensitivity and specificity of 84.6 and 79.3% respectively. Postoperative NT-ProBNP and soluble suppression of tumorigenicity 2 with cut-off values of 904.12 and 1.46 respectively showed significant association with readmission with sensitivity and specificity of 95.5% and 97.7% respectively for NT-ProBNP and sensitivity and specificity 84.6% and 74.7% respectively for soluble suppression of tumorigenicity 2. No laboratory parameter change showed significant association with readmission. Conclusion: Postoperative NT-proBNP levels were strongly related with readmission after juvenile congenital heart surgery, with good sensitivity and specificity.