Determining the prevalence of primary ciliary dyskinesia (PCD) in different populations has proved difficult, with estimates varying between one in 4000 to one in 40,000. The aim of this study was to determine the incidence of PCD in a well-defined highly consanguineous Asian population in the UK. Over a 15-year period all patients suspected of having PCD in the Asian population of Bradford, UK, were tested by measurement of ciliary beat pattern, frequency and electron microscopy. The prevalence of PCD in the population studied was one in 2265. 52% of the patients' parents were first cousins. All patients had a history of chronic cough and nasal symptoms from the first year of life. 73% had a history of neonatal respiratory distress. Clinical suspicion of PCD should be high in populations in which it is possible that high levels of consanguinity may result in an increase in those with PCD. In these communities the combination of chronic cough and nasal symptoms should prompt early diagnostic testing.