Postoperative results of surgical repair of complete transposition of the great arteries (TGA) with pulmonary hypertension (PH) in 19 patients in whom mean pulmonary arterial pressure was >50 mmHg or the pulmonary/systemic arterial pressure ratio was >0.8 were examined. TGA with intact ventricular septum was diagnosed in 10 patients and TGA with ventricular septal defect in 9. At the time of corrective surgery (arterial switch 10, atrial switch 9), patients ranged in age from 7 months to 14 years (mean 2.4 years). Seventeen patients (89%) survived with New York Heart Association functional class I. Seven patients in whom calculated pulmonary vascular resistance was 10-20 U m2 after surgery survived with subsequent regression of PH. Residual PH was diagnosed in 36% of survivors. Two patients in whom pulmonary vascular resistance was 26 and 36 U m2, respectively, died after surgery. In patients with TGA, severe PH was not necessarily fatal and was potentially reversible after successful surgery.