Late results were reviewed in 220 survivors after atrial correction of transposition of the great arteries who were operated between 1964 and 1985. Senning's procedure and its various modifications have been used; all patients who survived 30 days after correction were included in this analysis. Average follow-up for the whole group was 10.3 years; 113 patients were observed for 10 years, 26 patients for 15 years, and 8 patients for 20 years. The actuarial survival rate for the whole group was 89% at 10 years, 87% at 15 years, 82% at 20 years. It was higher in simple than in complex transposition (92% versus 84% at 10 years). Sudden deaths (8 patients) and late heart failure (6 patients) were the principal causes of death, predominantly in the complex transposition group (10/13 deaths). Late survival was more common in the latter part of the study, with 95% of patients operated on after 1978 surviving 9 years as opposed to 84% of patients operated on earlier. Late reoperation was necessary in 18 patients (8%), with 12 reoperations occurring within 2 years after correction. Cumulative reoperation rate reached 11.7% after 10 years. Reoperations were more common in complex than in simple transposition (14% versus 6%, p less than 0.05). Late arrhythmias can occur after atrial correction, and the cumulative incidence of pacemaker implantations was 8% at 10 years. Most of the survivors are functionally free of symptoms (83% of the simple and 75% of the complex transposition group). Significant tricuspid valve incompetence was encountered in only three patients, with two valve reconstructions being possible. In summary, long-term outlook for survivors of atrial correction for transposition of the great arteries remains encouraging, although complex transposition does seem to engender more late problems. Atrial correction is still warranted in simple transposition, but close cardiological surveillance is necessary.