OBJECTIVE: Different instruments are available to measure functional status in juvenile rheumatoid arthritis (JRA); however, none is based on the evaluation of joint range of motion (ROM). We designed and evaluated a ROM scale to be used as a complementary instrument in daily practice with JRA as well as in trials. METHODS: The 10 joint movements of the Pediatric Escola Paulista de Medicina Range of Motion scale (Pediatric EPM-ROM) were derived from 25 initial movements. The selection was based on 2 criteria: (1) consensus among 3 pediatric rheumatologists, one physical therapist, and one occupational therapist; and (2) choice of movements that presented the highest scores in a pilot study involving patients with JRA. The score for each joint ranges from 0 (full movement) to 3 (severe limitation) and the cutoff degrees of motion are, in general, based on the lack of ability to perform some activities of daily living. The test-retest reliability was assessed by administering the scale twice by the same observer, 4 to 10 days apart, always in the morning. The interobserver reliability was evaluated on the same day by 2 independent observers. Cross sectional construct validity was also assessed by correlating the values of some clinical variables with the scores of the Pediatric EPM-ROM scale. RESULTS: The instrument was applied to 34 patients with JRA, 11 systemic, 11 polyarticular, and 12 pauciarticular. The mean EPM-ROM score was 0.57 (SD 0.54, min 0, max 2.05). The test-retest and interobserver correlation coefficients were 0.96 and 0.98, respectively. The Pearson correlation coefficients comparing scores of the Pediatric EPM-ROM scale and other variables were satisfactory: Childhood Health Assessment Questionnaire, r=0.55 (p<0.001); American College of Rheumatology global functional class, r=0.56 (p<0.001); and number of limited joints, r=0.65 (p<0.001). CONCLUSION: Our results provide evidence that the Pediatric EPM-ROM scale is a valid instrument to measure joint ROM in JRA.