We analysed 60 consecutive patients who got Senning operation for transposition of the great arteries [TGA] with or without ventricular septal defects [VSD]. There were 41 simple TGA [group I] and 19 TGA with VSD [Group II], the operative mortality was 20 % [in group I 4.9 %, group II 52.6 %]. Among the survivors [n=48], the mean follow-up period was 7 years [range, 1 year to 13.5 years] and the actuarial survival rate at 13 years were 95 % in group I and 42 % in group II. Preoperative high left ventricular pressure and high pulmonary arterial pressure affected the surviving [p<0.01]. There occurred various type of arrhythmia like junctional rhythm, first degree atrioventricular [AV] block, sick sinus syndrome and complete AV block, and we inserted 2 permanent pacemakers for these patients. The incidence of arrhythmia were 28.2 % [11/39] in group I and 55.6 % [5/9] in group II, and the actuarial freedom from arrhythmia at 13 years after operation was 66 % [71 % in group I, 44 % in group II]. Increased aortic cross clamping time had affected the development of arrhythmia [p<0.05] which meant the complexity of the operation. The total incidence of left ventricular outflow tract obstruction [LVOTO] was 31.3 % [15/48], but only 3 patients [6.25 %] showed the significant gradient requiring reoperation. The pulmonary venous pathway obstruction [PVO] were found in 3 patients, all in group I, and among them only one required the reoperation. The estimated freedom from PVO was 89 % at 13 years [87 % in group I, 100 % in group II], but we couldn`t find any significant systemic venous obstruction in our series. There occurred 27.1 % [13/48] mild degree tricuspid valve regurgitation without necessary surgical correction. We experienced 14.6 % [7/48] reoperation rate: 3 residual VSD, 3 LVOTO, 1 PVO, 3 atrial baffle leakage. For this high incidence of complication rate after Senning operation and high mortality in TGA with VSD, We do not use this kind of surgical modality any more and do the Jatene operation for all the TGA patients since several years ago.