One hundred fifty-three lung lavage procedures were performed on 81 cystic fibrosis patients during the years 1963 to 1976. Local analgesia was used in 24 lavages done via a rigid bronchoscope and in a group of 73 lavages directed by a fiberoptic bronchoscope. No abnormalities in cardiac rate or rhythm were observed with the lavages directed by fiberoptic bronchoscope. Fifty-six lavages were performed under general anesthesia with 20 cardiac abnormalities being noted among this group. Subjective improvement was noted in 96% of the 56 patients who had lavage under general anesthesia. Objective improvement was apparent in 45% of the 24 patients who had lavage with the rigid bronchoscope and 64% of the 36 patients who had lavage by fiberoptic bronchoscopy. It is concluded that patients with cystic fibrosis of varying stages of disability can more safety (and with good improvement) have bronchial washouts with the fiber-optic bronchoscope than with either of the other two techniques.