Three techniques for the assessment of the integrity of the canine tympanic membrane were evaluated experimentally. Tympanometry, an objective technique, was shown to be very accurate for the evaluation of the integrity of the ear drum. Otoscopic examination by experienced personnel was shown to be moderately accurate under controlled conditions when the external ear canal was not inflammed. However, under field conditions when otitis externa was present, visual inspection of the tympanic membrane was seldom possible even after lavage of the ear. Palpation of the tympanic membrane with a blunt probe was shown to be very inaccurate and led to rupture of the tympanic membrane in a high proportion of cases. These results imply that two widely used techniques for the examination of the canine tympanic membrane are unsatisfactory. Furthermore, they suggest that previous reports of the prevalence of ear drum perforations in dogs may need reappraisal. Tympanometry is a non-invasive, objective and practical technique for the assessment of ear drum integrity which is worthy of further evaluation.