It is difficult to objectively measure pain in rheumatoid arthritis (RA). A behavioral observation method for the assessment of RA pain has been developed. In this study, videotapes were made of 53 RA patients while they performed standardized maneuvers. Trained raters viewed the videotapes and recorded the frequencies of 7 pain behaviors. Clinical and laboratory measures of rheumatoid disease activity also were recorded for each patient. Rheumatology fellows viewed 20 randomly chosen video recordings of the patients and made global estimates of the intensity and unpleasantness of pain. Significant positive correlations were found between total pain behavior scores and measures of disease activity. The fellows' estimates of the intensity and unpleasantness of the patients' pain also were significantly and positively correlated with the total pain behavior scores. The behavioral observation method may be useful in the assessment of RA pain and may be included as an objective outcome measure in clinical trials with RA patients.