Ciliary beat frequency (CBF) was measured at room temperature in nasal epithelial cells from 10 control individuals at multiple time points during sequential monolayer-suspension culture. CBF was 8.4 +/- 1.6 Hz in the biopsy and decreased in monolayer culture to approximately 6 Hz. During monolayer culture the interindividual variability was increased (3.0 Hz), but not the intercellular and intracellular variability. Immediately after ciliogenesis in suspension culture, CBF was approximately 8 Hz, with a low interindividual variability. After 3 weeks in suspension culture CBF was 8.6 +/- 0.9 Hz. There was no difference in intercellular and intracellular variability of CBF in the different culture conditions. Ciliogenesis in the sequential monolayer-suspension culture results in quantitative normal ciliary activity, with low variability. The most important parameter of ciliary activity that changes during ciliary deterioration and ciliogenesis is the CBF itself.