Objective. To assess the effects of methotrexate (MTX) therapy on radiologic progression in juvenile rheumatoid arthritis (JRA). Methods. We evaluated serial wrist radiographs for carpal length in 23 JRA patients with bilateral wrist involvement, before and during MTX treatment. These carpal length measurements were compared with established norms for carpal length in a healthy pediatric population. Results. Both clinical responders to MTX (17 of 23 patients) and nonresponders (6 of 23) had decreasing carpal length prior to initiation of the treatment. Eleven of the 17 clinical responders had improved carpal length after a mean of 2.5 years of MTX treatment. All 6 clinical nonresponders had progressive loss of carpal length. Conclusion. MTX treatment resulted in radiologic improvement, as measured by carpal length, in the majority of children with JRA who had a clinical response to MTX.