Patients who are diagnosed at any time with moderately to severely active polyarticular or polyarticular-course JIA, (defined as arthritis affecting greater than 5 joints at the time of diagnosis of polyarticular or polyarticular-course JIA), prescribed and treated in a routine clinical setting either with Humira® (adalimumab), or MTX. Approximately 800 patients will be enrolled in the United States, EU countries, and Australia. Approximately 40 to 45 physicians will be included based on participation in prior AbbVie Humira sponsored clinical JIA studies.