Five infants underwent intracardiac repair of truncus arteriosus (TrA) from June, 1993 through May, 1998. The patients weighed 2.4 to 5.71kg (mean 3.47) and their ages at operation ranged from 6 to 133 days (mean 38.2). The anatomical type of TrA was type I (Collet & Edwards classification) in all cases. We employed the Barbero-Marcial procedure for 4 infants and truncal valve replacement using a homograft for one in whom moderate truncal valve regurgitation (TrVR) and severe stenosis was detected by preoperative echocardiography. There was one operative death in an infants who presented with cardiogenic shock and moderate TrVR on admission. No patients in whom preoperative echocardiographic study showed less than mild TrVR died after surgery. Close observation after surgery is necessary because aggravation of TrVR may occur on a long-term basis.