The diagnosis of dysphagia in the dog requires an evaluation of a variety of signs that can be caused not only by a 'swallowing disorder' but also by several other pathological conditions. Most owners mention coughing, vomiting, regurgitation and nasal discharge, and the clinician must decide whether these signs are related to dysphagia. In this study a standardised questionnaire for the diagnosis and localisation of dysphagia was evaluated for its accuracy by comparing the results with contrast videofluorography as the definitive standard. The purpose of the study was to optimise the selection of dogs for more expensive diagnostic procedures such as videofluorography and electromyography. In a group of 69 dogs with 'swallowing problems' the questionnaire had a sensitivity of 0.97 and a positive predictive value of 0.94 for dysphagia in general. The questionnaire was also useful for the exclusion of oral phase dysphagia, with a specificity of 0.70 and a negative predictive value of 0.97. Most dogs with pharyngeal phase dysphagia could be detected by using the questionnaire (sensitivity 0.91). The questionnaire was not of specific value for the detection or exclusion of oesophageal phase dysphagia, for which it had a sensitivity of 0.69, a specificity of 0.57 and predictive values for positive and negative tests of 0.79 and 0.44, respectively.