The intrinsic ciliary beat frequency of human respiratory epithelium collected by 3 different biopsy techniques was examined. Ciliated epithelium was obtained by nasal brush, endobronchial brush, and endobronchial forceps biopsies from 15 patients during bronchoscopy, and ciliary beat frequency was determined in vitro at 37 degrees C using a photoelectric technique. The overall mean beat frequencies of nasal brush biopsy, endobronchial brush biopsy, and endobronchial forceps biopsy specimens were 14.3, 14.4, and 14.6 hertz, respectively. There were no significant differences (p greater than 0.05) in the overall means. Although for a given patient ciliary beat frequency was not significantly different between specimens obtained by the 3 different biopsy techniques, the pooled mean beat frequency varied from one subject to another (p less than 0.01).