Anti-TNFalpha agents are frequently used in the treatment of severe JIA. Etanercept, a fully human soluble recombinant tumour necrosis factor p75 receptor Fc fusion protein, has been registered for the treatment of polyarticular course JIA patients who fail to respond to or do not tolerate methotrexate (MTX). Infliximab, a chimeric human-mouse monoclonal antibody to TNFalpha, is expected to be registered soon for JIA and Crohn's disease (CD) in children. As in adults, both agents are effective in controlling inflammation and inhibiting the progression of joint destruction. Despite this good clinical efficacy, the physician must remain alert for potential side effects, especially after prolonged use. This review gives an overview of the reported adverse events.