Temporomandibular joint (TMJ) disease is uncommon in children but frequently occurs in juvenile rheumatoid arthritis (JRA). Involvement is often asymptomatic; however, it can lead to growth disturbances and facial deformity. Thirty TMJs in 15 children (11 girls and 4 boys aged 3.5-18 years) with JRA were evaluated clinically and by MRI. Plain films were reviewed when available. Magnetic resonance imaging parameters included T1-weighted and in some cases T2-weighted or gradient recall echo sequences. We assessed condylar configuration, glenoid fossa changes, presence of erosions, disk abnormality, range of motion, and presence of joint effusions or pannus. Abnormalities included cortical erosions (n = 19), disk thinning (n = 18), and perforation (n = 2). Reduction of joint movement (n = 20), joint locking (n = 3), and pannus/effusions (n = 5) were also found. Magnetic resonance imaging is a useful technique for the detection of TMJ involvement in JRA. Early detection and therapeutic intervention may lessen or prevent subsequent deformities.