OBJECTIVE: To evaluate safety and effectiveness of adalimumab (ADA) in polyarticular-course juvenile idiopathic arthritis (JIA) in the STRIVE registry. METHODS: STRIVE enrolled patients with polyarticular-course JIA into 2 arms based on treatment with methotrexate (MTX) alone or ADA with/without MTX (ADA ± MTX). Adverse events (AEs) per 100 patient-years of observation time were analyzed by registry arm. Patients who entered the registry within 4 weeks of starting MTX or ADA ± MTX, defined as new users, were evaluated for change in disease activity assessed by the 27-joint Juvenile Arthritis Disease Activity Score with the C-reactive protein level (JADAS-27CRP ). RESULTS: At the 7-year cutoff date (June 1, 2016), data from 838 patients were available (MTX arm n = 301, ADA ± MTX arm n = 537). The most common AEs were nausea (10.3%), sinusitis (4.7%), and vomiting (4.3%) in the MTX arm and arthritis (3.9%), upper respiratory tract infection (3.5%), sinusitis, tonsillitis, and injection site pain (3.0% each) in the ADA ± MTX arm. Rates of serious infection were 1.5 events/100 patient-years in the MTX arm and 2.0 events/100 patient-years in the ADA ± MTX arm. AE and serious AE rates were similar in patients receiving ADA with versus without MTX. No deaths or malignancies were reported. New users in the ADA ± MTX arm showed a trend toward lower mean JADAS-27CRP compared with new users in the MTX arm in the first year of STRIVE. CONCLUSION: The STRIVE registry 7-year interim results support the idea that ADA ± MTX is well tolerated by most children. Registry median ADA exposure was 2.47 (interquartile range 1.0-3.6) years, with 42% of patients continuing ADA at the 7-year cutoff date.