Although univentricular or biventricular repair is not always possible for hearts with single-ventricle physiology, it has been proven to produce a satisfactory outcome. It is hypothesized that patient prognosis can be predicted by anatomical diagnosis at presentation. Between 1961 and 1995, 158 patients with single-ventricle physiology, including tricuspid atresia and hypoplastic left heart syndrome, were referred to the authors' institute, and underwent 260 surgical interventions. Follow-up was 99% complete. Patient survival and anatomical risk factors were examined by the Kaplan-Meier method, and multivariate analysis including the Cox proportional hazard model. Mean (s.e.m.) actuarial survival rates at 1, 5, 10 and 20 years following birth were 70.3(3.6)%, 56.3(4.0)%, 48.8(4.2)%, and 40.9(4.7)%, respectively. Definitive palliation was attempted in 38 patients (univentricular in 35 and biventricular in three). Multivariate analysis identified systemic ventricular outflow tract obstruction, mitral atresia, situs ambiguus, and pulmonary vein drainage tract obstruction as independent prognostic factors for overall survival. Visceral heterotaxy was the only independent risk factor for lack of application or failure (death or take-down within 30 days of operation) of univentricular or biventricular repair. In conclusions, these anatomical factors in hearts with single-ventricle physiology affect long-term mortality, despite multiple and heterogeneous surgical efforts.