We reviewed our entire experience of 44 consecutive patients undergoing the arterial switch operation [ASO] for transposition of the great arteries [TGA] since March 1985.There were 28 patients with simple TGA[group I] and 16 with associated ventricular septal defect[VSD] [Group II] There were five hospital deaths[11.4%, 5/44], two related to single right coronary artery anatomy. There have been no late deaths. For group I hospital mortality was 14.3%[4/28], and for group II this was 6.25%[1/16]. Mean follow-up was 3.3 years[range 1 month to 8 years] and was completed for all patients. Actuarial survival at 7 years for hospital survivors was 85 $pm$ 3.2 % in group I and 94 $pm$ 3.5% in groupII. One patient has mild asymptomatic left ventricular outflow tract obstruction, and five patients [12.8 %,5/ 39] have right ventricular outflow tract gradients[RVOTO] exceeding 25 mmHg; only one patient has required reoperation for RVOTO. Mild neoaortic regurgitation is present in one patient. All survivors are currently in NYHA class I without medicalion, and all are in sinus rhythm. The ASO is associated with low operative risk and excellent medium-term outcome in most subsets of patients undergoing this operation. With more experience, improved results can be expected also in those patients currently at higher risk.