A significant amount of work has been performed over the past 2 years further defining the pathophysiology of juvenile idiopathic arthritis (JIA). The development of the biologic agent etanercept represents successful translational research. This genetically engineered fusion protein targets tumor necrosis factor, binding and inactivating this important component of inflammation. This advance has been accompanied by refinements in classification, as well as further elucidation of the natural disease course of JIA. Recent work continues to demonstrate the widespread nature of JIA, as well as its severity in adulthood.