Objective. To characterize variations in initial treatment for knee monoarthritis in the oligoarthritis subtype of juvenile idiopathic arthritis (OJIA) by pediatric rheumatologists and to identify patient, physician, and practice-specific characteristics that are associated with treatment decisions. Methods. We mailed a 32-item questionnaire to pediatric rheumatologists in the United States and Canada (n = 201). This questionnaire contained clinical vignettes describing recent-onset chronic monoarthritis of the knee and assessed physicians' treatment preferences, perceptions of the effectiveness and disadvantages of nonsteroidal antiinflammatory drugs (NSAID) and intraarticular corticosteroid injections (IACI), proficiency with IACI, and demographic and office characteristics. Results. One hundred twenty-nine (64%) questionnaires were completed and returned. Eighty-three percent of respondents were board certified pediatric rheumatologists. Respondents' treatment strategies for uncomplicated knee monoarthritis were broadly categorized: initial IACI at presentation (27%), initial NSAID with contingent IACI (63%), and initial NSAID with contingent methotrexate or sulfasalazine (without IACI) (10%). Significant independent predictors for initial IACI were believing that IACI is more effective than NSAID, having performed > 10 IACI in a single patient at one time, and initiating methotrexate via the subcutaneous route for OJIA. Predictors for not recommending initial or contingent IACI were believing that the infection risk of IACI is significant and lacking comfort with performing IACI. Conclusion. There is considerable variation in pediatric rheumatologists' initial treatment strategies for knee monoarthritis in OJIA. This variation is primarily associated with perceptions of medication effectiveness and proficiency with IACI. Further studies are warranted to clarify the optimal treatment of OJIA.