It is known that low birth weight is a risk factor for poor outcome in cardiac surgery for many cardiac defects. Truncus arteriosus is a rare congenital anomaly that has an unfavorable natural course. We report a successful surgical correction of truncus arteriosus in an 13-day-old premature infant with body weight of 1.5 kg and gestational age of 32 weeks. We used autologous untreated pericardial conduit without valve in right ventricular outflow reconstruction. The patients remains in good condition with normal body weight (50 percentile) and wide right ventricular outflow tract 20 months after the operation.