Eighty patients with a diagnosis of either rheumatoid arthritis, localised osteoarthritis, or generalised osteoarthritis were asked to describe their pain by selecting words from a standardised list of pain descriptors. Words on this list were taken from the sensory class of pain descriptors found in the McGill pain questionnaire. Discriminant analysis was used to identify distinctive characteristics for each of these pain syndromes. On the basis of this analysis verbal responses for each patient were classified into one of the three diagnostic categories. Correct classification occurred in 65% of cases. An estimate of the technique's performance in prospective validation was derived by a split sample approach.