An infant with truncus arteriosus, complete atrioventricular canal, and total anomalous pulmonary venous connection successfully underwent one-stage complete repair. Residual mitral valve regurgitation required reoperation after 12 days. The patient is doing well at 6 months' follow-up. Echocardiography demonstrates no residual defects, competent atrioventricular valves, and normal pulmonary pressure. This case illustrates the potential for successful one-stage repair even of associated complex heart defects involving venous, intracardiac, and arterial pathways.