It has been suggested that patients with bronchiectasis might have increased central microtubular orientation angle (CMOA), which leads to poor coordination of ciliary beating, and consequently impairment of airway defence. We have employed transmission electron microscopy to assess CMOA of ciliated nasal mucosa in a cohort of 133 (81F, 56.8+/-16.1yr) stable bronchiectasis and 59 healthy subjects (30F, 49.3+/-22.1yr). There was no significant difference in CMOA between bronchiectasis (13.2 degree) and control subjects (13.0 degree, P=0.82). There was no significant difference in CMOA among patients according to the etiology of bronchiectasis, presence of nasal symptoms, or sputum status of Pseudomonas aeruginosa infection. Patients with more severe bronchiectasis, i.e. those with FEV(1) <60%, FVC <60%, or more than 4 bronchiectatic lung lobes, had significantly lower CMOA than their counterparts (P<0.05). There was no correlation between CMOA with age, 24h sputum volume, exacerbation frequency, FEV(1), FVC, or the number of bronchiectatic lung lobes (P>0.05). CMOA correlated with ciliary beat frequency (negative), and the percent of cilia showing ultrastructural or microtubular defects (P<0.05). Central microtubular orientation angle does not correlate with clinically important parameters, in contrary to the results reported by previously published smaller scale studies.