Between October 1974 and March 1, 1985, 26 patients with 29 anomalous AV bypass tracts underwent surgical treatment at the Medical Center of UAB, with follow-up from 1 to 14 years. Eleven of the patients underwent surgical correction of major associated cardiac anomalies. One patient had His bundle ablation, and 25 patients had direct surgical division of 28 bypass tracts with the use of an endocardial approach. Successful division was achieved in 27 (96%; confidence limits 88% to 99%) of 28 bypass tracts identified pre- and intraoperatively. There were no hospital deaths, but on formal follow-up there were three late deaths, all occurring in patients with major associated cardiac pathology. Neither preexcitation nor reciprocating tachycardia recurred, and functional status was excellent among patients without associated cardiac lesions. Because of the safety and, at least on intermediate-term follow-up, apparently curative nature of this operation (particularly for patients without other major cardiac pathology), surgical treatment is recommended for patients with bypass tracts having lethal potential, those with reciprocating tachycardia unresponsive to drugs, and to symptomatic patients facing many years of medications.