['The aim of this study is to compare self-reported health-related quality-of-life (HRQoL) with the objective of exercise performance in patients with congenital heart disease (CHD) according to diagnosis.', '564 patients (255 females, 14-73 years) with various CHD (62 shunt, 66 left heart obstruction, 33 PS/PR, 47 Ebstein, 96 Fallot, 98 TGA after atrial switch, 38 other TGA, 31 Fontan, 32 palliated/native cyanotic, 61 others) and a group of 53 healthy controls (18 females, 14-57 years) completed a QoL questionnaire (SF-36) and performed a symptom-limited cardiopulmonary exercise test. Despite several limitations at exercise (P = 1.30 x 10(-33)), patients only reported reductions in HRQoL concerning physical functioning (P = 4.41 x 10(-15)) and general health (P = 6.17 x 10(-5)) and not psychosocial aspects. This could be confirmed in all diagnostic subgroups. Correlation to peak oxygen uptake was found in physical functioning (r = 0.435, P = 1.72 x 10(-27)) and general health (r = 0.275, P = 3.79 x 10(-11)). However, there was severe overestimation of physical functioning in most patients when compared with actual exercise test results.'] Does self-estimated physical functioning poorly predict actual exercise capacity in adolescents and adults with congenital heart disease?