We evaluated laboratory and radiological findings and examined tracheobronchial cilia by transmission electron microscopy in 9 patients with primary ciliary dyskinesia (PCD), in order to elucidate the clinical pictures of PCD and the relationship between PCD and diffuse panbronchiolitis (DPB) which was proposed as a new disease entity in Japan in 1969. The clinical pictures of our PCD patients were almost the same as that already described in several articles in Europe and North America; early onset of respiratory symptoms, high incidence of chronic sinusitis and otitis media exudative as well as infertility, continuous infections in the lower respiratory tracts (Hemophilus influenzae, Pseudomonas aeruginosa etc.). Tracheobronchial cilia obtained by brushing technique were immotile (6 out of 8 patients) or dyskinetic (2 out of 8 patients). Ultrastructural study of cilia revealed the lack of dynein arms in all patients: the lack of both outer and inner arms (4 patients), the lack of outer arms (2 patients), the lack of inner arms (2 patients). Chest X-ray films revealed situs inversus in six out of nine patients. According to the radiological findings (chest X-ray film, CT-scan, bronchogram), the patients were divided into three groups; I: localized bronchiectasis (5 patients), II: diffuse micronodular lesions without definite bronchiectasis (3 patients), III: diffuse micronodular lesions with bronchiectasis (1 patient). Two patients of the second group satisfied the clinical diagnostic criteria for DPB (Chest 83:63, 1983). In conclusion, PCD can cause a variety of respiratory tract lesions such as bronchiectasis, DPB and other types of peripheral airway disorders.