Between January 1, 1975, and December 31, 1988, 233 patients were operated on for correction of tetralogy of Fallot (TOF). Mean follow-up was 13.9 years (median 7.65 years) and was 99.6% complete. Actuarial survival was 84 +/- 3%. The risk of death decreased gradually to a constant rate of 0.00034 deaths/month by the 6th postoperative month. There were 22 early deaths, due mostly to Low Output Syndrome. The principal incremental risk factor was the postrepair ventricular pressure ratio (PRV/LV) (P less than 0.0001). Other factors were: patent ductus arteriosus (PDA; P = 0.02), other associated anomalies (P = 0.005), higher preoperative hemoglobin levels (P = 0.06) and use of transannular patches (P = 0.02). The operative risk was significantly reduced by a recent operative date (P = 0.01) and by an older age at operation (P = 0.12). Among 8 late deaths, 2 were unrelated to the cardiac condition, 2 occurred suddenly, 3 were due to congestive heart failure and the last was due to reoperation for patch endocarditis. The risk of late death was significantly higher in patients operated on at an older age (P = 0.04). There were 10 open heart reoperations: 5 for patch dehiscence, 4 for residual pulmonary stenosis and 1 for residual atrial septal defect. The reoperation-free actuarial survival was 82 +/- 3%. With the present operative standards, the parametric operative risk of an average patient with simple TOF (hemoglobin = 12 g, PRV/LV = 0.5) is 0.7%. Where the TOF is severely cyanotic (hemoglobin = 25 g) and the pulmonary arteries are severely restricted, the average mortality is 30%.(ABSTRACT TRUNCATED AT 250 WORDS)