Between March 1988 and March 1991, 17 patients underwent bilateral lung transplantation for end-stage lung disease caused by cystic fibrosis. There were 11 male and six female patients. Ages ranged from 19 to 41 years (mean age 28 years). Preoperative mean arterial oxygen tension with the patient breathing room air was 54 +/- 6 mm Hg; forced vital capacity, 1.8 +/- 0.7 L; forced expiratory volume in 1 second, 0.9 +/- 0.3 L; and 6-minute walk test, 506 +/- 44 m. Immunosuppression consisted of cyclosporine, azathioprine, and prednisone. Induction immunosuppression was obtained with Minnesota antilymphocyte globulin. All patients received perioperative antibiotics according to sputum cultures and sensitivities. There were six operative deaths, four of which resulted from bacterial infection. Two patients required a second transplantation, one receiving a single lung and one undergoing bilateral lung replacement. Significant functional improvement was observed in all survivors. At 3 months follow-up, mean arterial oxygen tension on room air was 95 +/- 6 mm Hg (p less than 0.01); forced vital capacity, 3 +/- 0.8 L (p less than 0.01); forced expiratory volume in 1 second, 2.6 +/- 0.9 L (p less than 0.01); and 6-minute walk test, 678 +/- 47 m (p less than 0.01). The actuarial survival rate was 66% at 3 months and 58% at 6, 12, and 24 months. The most frequent cause of morbidity and mortality was acute pneumonia resulting from Pseudomonas cepacia. For patients with respiratory failure caused by cystic fibrosis, bilateral lung transplantation is an effective treatment option associated with significant functional improvement.