A prevalence study was made of the most common clinical signs of mandibular dysfunction in a sample population of 1,000 patients in a general dental practice. Palpable joint irregularities (joint sounds) were found in about a third of the sample. All other frequencies were relatively low. Females had consistently higher frequencies than males, although the differences were generally not significant. A methodology that was quantified for the first time in relation to muscle palpation was used. Results of this study would indicate that the prevalence of the major clinical signs of mandibular dysfunction in the population expected to be seen in a general dental practice is not high and, furthermore, that their occurrence in the absence of pain does not necessarily indicate a need for treatment.