The indications for single, bilateral, and heart-lung transplantation for patients with pulmonary hypertension remain controversial. We retrospectively analyzed the results from 11 single, 22 bilateral, and 24 heart-lung transplant procedures performed between January 1989 and January 1993 on 57 consecutive patients with pulmonary hypertension caused by primary pulmonary hypertension (n = 27) or Eisenmenger's syndrome (n = 30). Candidates with a left ventricular ejection fraction less than 35%, coronary artery disease, or Eisenmenger's syndrome caused by surgically irreparable complex congenital heart disease received heart-lung transplantation. All other candidates received single or bilateral lung transplantation according to donor availability. Although postoperative pulmonary artery pressures decreased in all three allograft groups, those in single lung recipients remained significantly higher than those in bilateral and heart-lung recipients. The cardiac index improved significantly in only the bilateral and heart-lung transplant recipients. A significant ventilation/perfusion mismatch occurred in the single lung recipients as compared with bilateral and heart-lung recipients because of preferential blood flow to the allograft. Graft-related mortality was significantly higher and overall functional recovery as assessed by New York Heart Association functional class was significantly lower at 1 year in the single as compared with bilateral and heart-lung recipients. Thus bilateral lung transplantation may be a more satisfactory option for patients with pulmonary hypertension with simple congenital heart disease, absent coronary arterial disease, and preserved left ventricular function. Other candidates will still require heart-lung transplantation.