The study was designed to assess the long-term results of one and one-half ventricular repair on systemic and pulmonary circulation, right ventricular growth and function, and the prevalence of arrhythmias. Eighty-four patients undergoing one and one-half ventricular repair between January 1990 and December 2003 were studied. Age was 4 to 504 months (mean, 47.9 ± 57.3 months). Sixty-nine survivors underwent serial echocardiography, radionuclide studies, cardiac magnetic resonance imaging, and cardiac catheterization. Operative and late mortality were 10.7% and 8%, respectively. Perioperative and postoperative supraventricular arrhythmias were observed in 14.3% and 15.9% of patients, respectively. Risk factors for supraventricular arrhythmias included systemic ventricular dysfunction, heterotaxy syndrome, and Ebstein’s anomaly. Mean late postoperative superior vena caval pressure was 14.2 ± 1.52 mm Hg and right atrial pressure was 6.6 ± 0.74 mm Hg. At a median follow-up of 87 months, actuarial survival was 81.9% ± 0.04%, and 89.8% were in New York Heart Association class I or II. Serial cine–magnetic resonance imaging demonstrated significant growth of tricuspid valve and right ventricular cavity in 45% of patients. One and one-half ventricular repair can be performed with an acceptable risk. The operation maintains a low pressure in the inferior vena caval tributaries, and reverses the Fontan paradox. Patients with tripartite right ventricles demonstrated a tendency toward enlargement of the pulmonary ventricular chamber commensurable with somatic growth.