Objective. There is wide variation in therapeutic approaches to systemic juvenile idiopathic arthritis (JIA) among North American rheumatologists. Understanding the comparative effectiveness of the diverse therapeutic options available for treatment of systemic JIA can result in better health outcomes. The Childhood Arthritis and Rheumatology Research Alliance (CARRA) developed consensus treatment plans and standardized assessment schedules for use in clinical practice to facilitate such studies. Methods. Case-based surveys were administered to CARRA members to identify prevailing treatments for new-onset systemic JIA. A 2-day consensus conference in April 2010 employed modified nominal group technique to formulate preliminary treatment plans and determine important data elements for collection. Followup surveys were employed to refine the plans and assess clinical acceptability. Results. The initial case-based survey identified significant variability among current treatment approaches for new-onset systemic JIA, underscoring the utility of standardized plans to evaluate comparative effectiveness. We developed 4 consensus treatment plans for the first 9 months of therapy, as well as case definitions and clinical and laboratory monitoring schedules. The 4 treatment regimens included glucocorticoids only, or therapy with methotrexate, anakinra, or tocilizumab, with or without glucocorticoids. This approach was approved by >78% of the CARRA membership. Conclusion. Four standardized treatment plans were developed for new-onset systemic JIA. Coupled with data collection at defined intervals, use of these treatment plans will create the opportunity to evaluate comparative effectiveness in an observational setting to optimize initial management of systemic JIA. © 2012, American College of Rheumatology.