The effect of counselling and occlusal adjustment was investigated in thirty patients with mandibular dysfunction involving the temporomandibular joint (TMJ). The patients were examined at three visits 6 weeks apart. At the first visit all patients received counselling. At the second visit they were divided into two groups, one receiving occlusal adjustment and the other not receiving treatment. The degree of mandibular dysfunction was assessed by the patients according to a five grade scale and by the clinical dysfunction index according to Helkimo (1974a). The score of subjective dysfunction was reduced significantly during the period following counselling and 60% of the patients improved. No effect was found on the clinical dysfunction score. The score of clinical dysfunction was reduced significantly during the period following occlusal adjustment and 67% of the patients improved. No further effect could be detected on the subjective dysfunction score. The correlation between changes in subjective and clinical dysfunction was poor, but changes in the subjective score were generally associated with changes in the clinical score. It was concluded that counselling may reduce the subjective symptoms; and occlusal adjustment the clinical signs of mandibular dysfunction involving the TMJ, but that the individual variation in response is substantial.