A variety of clinical measures are available for assessment of disease status of children with juvenile idiopathic arthritis (JIA) in clinical trials, clinical care and long-term outcome surveys. The American College of Rheumatology (ACR) Pediatric 30 remains the preferred primary outcome measure for registrative trials, although in most therapeutic studies performed in the 2000s patients were also evaluated for more stringent levels of improvement, that is, applying the ACR Pediatric 50, 70, 90, and 100 response criteria. Because the recent therapeutic advances have made inactive disease an achievable goal in most patients, it has been suggested that endpoints for future clinical trials incorporate the evaluation of disease activity state, namely the assessment of inactive disease and low disease activity. The introduction of the Juvenile Arthritis Disease Activity Score (JADAS) and the establishment of its cut-offs for various disease activity states may foster the implementation of the treat-to-target strategy in both clinical trials and routine practice. In recent years, there has been an increased focus on the inclusion of patient and child perspectives in health outcome measures through the use of parent/child-reported outcomes. Integration of these measures in the clinical evaluation is considered important as they reflect the parent's and child's perception of the disease course and effectiveness of therapeutic interventions. Future studies will show whether the newer imaging modalities, namely magnetic resonance imaging and ultrasound, can replace conventional radiography for the assessment of structural joint damage and its progression.