This Phase 4 open-label, nonrandomized multicenter registry study is being conducted to evaluate the long-term safety of ENBREL(R) (etanercept) compared to methotrexate in patients aged 2 to 18 years with polyarticular-course or systemic-onset juvenile rheumatoid arthritis (JRA). Patients will be evaluated for a total of 3 years. The registry will include patients who have recently started and are currently receiving ENBREL alone, ENBREL in combination with methotrexate or other disease-modifying antirheumatic drugs (DMARDs), methotrexate alone, or methotrexate in combination with other DMARDs. Approximately 600 patients will be enrolled at sites in the United States and Canada, with 400 patients receiving ENBREL and 200 receiving methotrexate without ENBREL. One group of patients will receive ENBREL by subcutaneous (SC) injection twice a week for up to 3 years and may continue taking other medicines such as prednisone or methotrexate. Another group will continue to receive methotrexate, either alone or in combination with DMARDs other than ENBREL. Candidates will be screened with a medical history and physical examination, including height, weight, and Tanner scores. A behavioral assessment, quality of life assessment, and physician's global assessment of disease activity will be performed. A blood test and joint evaluation will also be done. Both treatment groups will have on-study evaluations at baseline and months 3, 6, 9, 12, 18, 24, 30, and 36. Each follow-up visit will include a repeat of the screening assessments and an evaluation of adverse events or toxicity, including psychiatric and behavioral effects and new symptoms of autoimmune disorders. The two groups will be compared for safety, including effects on growth and development parameters. Patients will need to purchase or arrange the purchase of commercially available ENBREL. Patients entering the study during the period when ENBREL is in short supply will be able to obtain ENBREL after enrolling in the ENBREL Enrollment Program. Patients will receive ENBREL enrollment information at the time of registration into the study.