ALTHOUGH aural barotrauma among divers is a fairly common occurrence, most reports in the literature are confined to clinical descriptions of the condition.1-3 Lundgren4 in Sweden in 1965 reported the results of a questionnaire distributed among sports and recreational divers in that country, and Maspetiol et al5 have described some of the medicolegal problems of aural barotrauma in compressed air workers. Aural barotrauma frequently occurs in trainee divers in the early stages of their training and results from the inability of the trainee to "clear his ears" a term used to describe the ventilation of the middle ear cavity usually by the Valsalva maneuver.6 As well as causing discomfort and loss of diving practice, aural barotrauma causes a high proportion of failures in diving courses. For these reasons a survey of aural barotrauma among naval divers was planned at the Royal Australian Navy School of Underwater