Survival after entry and survival after repair (94%, 91%, and 91% at 1 month, 1 year, and 5 years, respectively) were similar in two institutions treating 196 consecutive patients, and there was no advantage (and a possible disadvantage) of a protocol of preliminary shunting and later repair in very young patients. Size and configuration of the right and left pulmonary arteries had no demonstrable effect on survival, prevalence of transannular patching, or postrepair right ventricular-left ventricular pressure ratio. Small size of the pulmonary "anulus" and trunk were risk factors for death, transannular patching, and high postrepair pressure ratio. High postrepair pressure ratio was a risk factor for death after repair. Very young age (less than about 3 months) was a risk factor for death after repair, particularly when other risk factors coexisted. The prevalence of transannular patching in patients with mild infundibular and pulmonary anulus and trunk hypoplasia decreased across the time of the study, without ill effect. The usefulness of measuring postrepair right ventricular-left ventricular pressure ratio is emphasized by the data.