Pediatric subjects age 2 to < or = 18 years of age with polyarticular course or systemic JRA who have recently started and are currently receiving: etanercept alone or in combination with methotrexate or other DMARDs; methotrexate alone or in combination with other DMARDs.The population includes pediatric subjects who completed Immunex protocol 016.0028 and selected other Immunex protocols will be eligible for this study once they change to marketed etanercept.