Survival before definitive operations was studied in 191 infants with double-inlet ventricle presenting before 1 year of age (1973 to 1988, median follow-up 8.5 years). The morphologic spectrum was broad, with a great prevalence of associated lesions. The actuarial survival rate before definitive repair was 57% at 1 year, 43% at 5 years, and 42% at 10 years, worse than prior reports because of the younger age at entry into our series. Analysis of univariate risk factors established that right atrial isomerism (18% of the group, relative risk 2.9), common atrioventricular orifice (42%, 2.0), pulmonary atresia (20%, 3.4), obstruction of the systemic outflow tract (18%, 2.5), and extracardiac anomalous pulmonary venous connection (13%, 3.1) were strongly associated with poorer survival. Pulmonary stenosis (40%, 0.35), balanced pulmonary blood flow (9%, 0.40), and presentation at an older age (3%, 0.42 to 0.18) were beneficial (p less than 0.05 to 0.0001). Multivariate analysis allowed the creation of patient-specific curves for prediction of survival for different anatomic and physiologic variants of double-inlet ventricle. A simple additive index was then derived from the multivariate Cox coefficients to enable stratification of risk for these morphologic subgroups of patients and so assist in the making of clinical decisions in infancy.