Background: Ventricular septal defect (VSD), accounts for up to 40% of all cardiac malformations. Defects that are present alone or in conjunction with other congenital cardiac abnormalities can be diagnosed. The conduction system, particularly the bundle of his and its branches, is susceptible to harm when the individual sutures are inserted. A permanent pacemaker is typically needed if a heart block occurs during or after therapy. Objective: we aimed to evaluate the incidence of conductive disorders after surgical VSD closure. Patients and Methods: A prospective observational study was conducted on 100 patients < 18 years with VSD from 2019 to 2021 at the Cardiothoracic Surgery Department of Cairo University Hospitals and Atfal Masr children's hospital. They had a clinical diagnosis of VSD and are referred for elective surgical VSD closure either including isolated VSD or combined with other intracardiac lesions. Results: The peri-membranous defect was the most common type and most VSD lesions were of moderate diameter. The mean ICU stay was 2.91 days. Abnormal rhythm occurred in 12 patients (12%). The most common conductive disturbance that occurred was incomplete right bundle branch block (RBBB) (6%), but complete heart block (CHB) occur in 1% which need a permanent pacemaker, bleeding happened in 2 (2%) patients and one patient died. Regarding the comparison between populations with post-operative normal rhythm and conductive disturbance, there was a significant difference in VSD types and diameter. Conductive disorder in surgical VSD closure was mostly associated with a larger diameter, Peri-membranous, and doubly committed VSD. Conclusion: VSD repair is considered to be a safe procedure with a very low mortality rate. In this study, we found out that large VSD was the most associated risk factor for conductive disturbance occurrence in VSD patients.