In western Sweden, less than one-third of children born with complete transposition between 1964 and 1983 are long-time survivors. During bicycle ergometry, using a steady-state protocol with analyses of the expiratory gases and lactate, we investigated the exercise capacity in survivors of atrial redirection. There were 16 patients who had a Mustard procedure, now aged 16.9±3.6 years (12.0–22.0) and 15 patients who underwent a Senning correction aged 9.4±1.6 years (7.2–12.1). Nineteen percent of Mustard cases and 53% of Senning cases had minor or no sequels. Moderate sequels were found in 44% of post-Mustard cases, and 40% of post-Senning cases, including baffle complications, moderate systemic ventricular dysfunction, sinus node dysfunction and tracheal stenosis. Severe problems were encountered in 37% of post-Mustard cases and 7% of post-Senning cases, including pulmonary hypertension, pulmonary venous obstruction, atrioventricular block and hemiparesis. The maximal exercise capacity was low (p<0.0001); 71% had an oxygen uptake below −2 SD of predicted values, with severely impaired oxygen uptake in all except one of the cases with severe sequels, but no significant difference was found between patients having mild and moderate sequels. The maximally achieved heart rate was low (p<0.0001); 71% had values below −2 SD of predicted, including all cases with sinus nodal dysfunction, as well as 40% of cases without it. The maximal oxygen pulse was low (p<0.01), below −2 SD in 36%, but it was less affected than other exercise variables in 68% of the patients. Our study, therefore, presents exercise data in an epidemiologically-based population, relates the data to postoperative sequels and discusses some possible adaptive mechanisms.