For years it was thought that the disorder of adaptive immunity is critical in the pathogenesis of juvenile idiopathic arthritis (JIA). However, the results of recent studies emphasize the importance of innate immunity and especially the role of alarmins, a group of multifunctional proteins that are released into the intercellular space during tissue injury or inflammation, mobilizing and activating the cells of innate immunity. These data indicate that inflammation triggered by alarmins plays a role in the pathogenesis of JIA. Furthermore, alarmins may serve as inflammatory markers and targets of therapy.