Apert syndrome is one of the craniosynostosis syndromes and is commonly associated with conductive hearing loss, but there are contradicting reports regarding the cause. Retrospective analysis of case notes of Apert syndrome patients seen between 1970 and 2003 was therefore undertaken. Seventy case notes were obtained; 59% were males. The incidence of congenital hearing impairment was 3-6%. Almost all had otitis media with effusion, which tends to persist into adulthood. More than 56% developed permanent low frequency conductive hearing loss by 10-20 years of age.