Background: Congenital heart disease is the most common causes of major congenital malformations. Congenital heart disease (CHD) represents, globally, 28% of all congenital anomalies, with a prevalence of about 8 to 10 per 1000 people live births, and they mostly require corrective surgery. Objective: To describe outcomes of congenital heart surgery in children under 15 years in Vientiane, Lao PDR. Methods: We undertook retrospective analyses of children with CHD who underwent cardiac surgery by the ASD teams at the Laos-Luxembourg Heart Center, Mahosot Hospital, Vientiane Capital, by reviewing the medical charts of patients discharged during 1st January 2014 to 31st December 2018. Results: Of a total of 415 patients with CHD, 185 underwent cardiac surgery that were the simple lesion 62.1%; moderate lesion 36.0%, complex lesion 1.6%, respectively. The patients who met the inclusion criteria in this study were 158 with a median age of 51 months and those with preschool age of 52.0%. Corrective surgery was the commonest conducted at 98.1%. The major procedure was VSD closure at 34.8%. The post-operative complication found in 30.0%. Overall in hospital mortality rate was 8.8% (by RICHS-1 method). Conclusion Congenital heart disease surgery in children under 15 years old at Laos-Luxembourg Heart Center, Mahosot Hospital was significantly associated with post-operative complications and high mortality. Therefore, trainings on CHD surgery and Post-CHD surgery care must be urgently organized to the Lao cardiac surgeons and nurses to reduce complications and deaths.