AbstractPrimary ciliary dyskinesia and heterotaxy are rare but not mutually exclusive disorders, which result from cilia dysfunction. Heterotaxy occurs in at least 12.1% of primary ciliary dyskinesia patients, but the prevalence of primary ciliary dyskinesia within the heterotaxy population is unknown. We designed and distributed a web-based survey to members of an international heterotaxy organisation to determine the prevalence of respiratory features that are common in primary ciliary dyskinesia and that might suggest the possibility of primary ciliary dyskinesia. A total of 49 members (25%) responded, and 37% of the respondents have features suggesting the possibility of primary ciliary dyskinesia, defined as (1) the presence of at least two chronic respiratory symptoms, or (2) bronchiectasis or history of respiratory pathogens suggesting primary ciliary dyskinesia. Of the respondents, four completed comprehensive, in-person evaluations, with definitive primary ciliary dyskinesia confirmed in one individual, and probable primary ciliary dyskinesia identified in two others. The high prevalence of respiratory features compatible with primary ciliary dyskinesia in this heterotaxy population suggests that a subset of heterotaxy patients have dysfunction of respiratory, as well as embryonic nodal cilia. To better assess the possibility of primary ciliary dyskinesia, heterotaxy patients with chronic oto-sino-respiratory symptoms should be referred for a primary ciliary dyskinesia evaluation.