The nasal ciliary beat frequency of 120 individuals in a British urban population was determined from nasal brushings. These individuals formed part of a previous study which looked at nasal and middle ear ciliary beat frequency in 60 patients with middle ear disease and compared it to nasal ciliary beat frequency in 60 matched controls. The present study intended to investigate any changes in nasal ciliary beat frequency with age. Comparison was also made between patients who were habitually exposed to tobacco smoke and non-exposed individuals. Nasal brushings were taken from the inferior turbinate using a cytology brush and the beat frequency was determined using a computerized photometric technique. In the population studied ages ranged from 2 to 69 years (mean 10.9 +/- 19.7 years). The mean beat frequency of 120 individuals was 11.5 +/- 2.5 Hz (SD), range 5.5-19.2 Hz. There was no particular trend observed with regards to beat frequency and advancing age. Nasal ciliary beat frequency in tobacco smoke-exposed patients (whether active or passive smokers) was significantly less than that in non-smoke exposed controls (P = 0.02, Student's t-test).