The safety of low-dose prednisone before and immediately after heart-lung transplantation. Preoperative steroid use has been considered a contraindication to heart-lung as well as lung transplantation. Moreover, most centers delay prednisone administration until 2 to 3 weeks postoperatively until airway healing is secure. We have performed 19 heart-lung transplantations and four single-lung transplantations since 1983. Five recipients (4 heart-lung, 1 single lung) had received prednisone, 5 to 40 mg daily, for 2 to 10 years preoperatively. All recipients were administered prednisone, 0.5 mg/kg daily, starting on postoperative day 1, with a taper to 0.2 mg/kg daily by 4 weeks. Minnesota antilymphocyte globulin (for 10 days), cyclosporine, and azathioprine were also employed. Bronchoscopy, lavage, and transbronchial biopsies were performed every 2 weeks for 3 months postoperatively. No patient had a serious airway complication; 2 heart-lung recipients, not on prednisone preoperatively, had a minor tracheal slough detected on bronchoscopy that resolved spontaneously. Actuarial survival after heart-lung transplantation is 84% +/- 8% and 69% +/- 16% at 1 year and 2 years, respectively. We conclude that prednisone commencing at a dose of 0.5 mg/kg daily from the first postoperative day is a safe practice after heart-lung transplantation. The long-term use of low-dose prednisone before heart-lung transplantation does not preclude normal tracheal healing. The safety of prednisone before and immediately after single-lung transplantation awaits confirmation by further experience. 