Aim.: The study aims to describe the long-term cardiological and psychological results of our first surgical cohort of arterial switch operation (ASO) patients and compare the results with our earlier series of Mustard patients. Methods.: Twenty-four survivors of ASO operated in our center (1985-1990) were evaluated by electrocardiography, echocardiography, magnetic resonance imaging, exercise testing, 24-hour Holter-monitoring, and health-related quality of life questionnaire. The results were compared with 58 adult Mustard patients who were evaluated in 2001 using the same study protocol. Results.: Arterial switch operation was performed at a median age of 13 days and Mustard operation at 2 years. Median follow-up was 22 years (range 20-25) and 25 years (22-29), respectively. After ASO, survival was better (P =04). The event-free survival after 22 years was 77% after ASO vs. 44% after Mustard (P =03). Good systemic ventricular function was present in 93% after ASO vs. 6% after Mustard (P <.01). Exercise capacity in ASO was 85% of predicted, compared with 72% in Mustard patients (P =01). Aortic regurgitation was found in 21% of ASO patients vs. 16% in Mustard patients. Arterial switch patients vs. Mustard patients reported significantly better quality of life and less somatic complaints. Conclusion.: The progression made in surgical treatment for transposition of the great arteries from Mustard to ASO has had a positive impact on survival, cardiac function, exercise capacity, and also self-reported quality of life and somatic complaints. Longer follow-up is warranted to monitor aortic regurgitation.