AbstractDetailed clinical, psychological and illness behaviour information was obtained from 43 patients with temporomandibular joint pain dysfunction. A discriminant function analysis was performed on the multiple variables to test their effectiveness as predictors of a successful response to simple conservative therapy. The questionnaire and statistical methodology employed are described in detail. It was found that clinical, psychological, and illness behaviour factors when used alone were poor predictors (less than 60 per cent) of treatment outcome. However, grouping clinical and psychological factors resulted in over 80 per cent successful prediction.