Atrial septotomy with inflow occlusion technique is well accepted palliative treatment for infants with cogenital anomaly of transposition of the great vessels. We have recently experienced a complete transposition of the great vessels in an one month old infant. Balloon atrial septotomy was initially done with gradual recurrence of cyanosis, which necessitated surgical form of atrial septotomy in 2 weeks. Atrial septotomy was performed with success with inlfow occlusion method and discussed problems concerning its surgical technique.