Since pediatric rheumatology diseases are rare, multicenter and even international collaboration is necessary to perform meaningful research. Multicenter research can enable rapid enrollment of sufficient numbers of patients for studies of epidemiology, diagnostic and classification criteria, genetic disease predisposition, pathogenesis, outcome and treatment protocols. In the last 20 years the vision of few has become a reality of collaboration of several hundred centers around the world in pediatric rheumatology research. In this paper we will describe the evolution of this international collaboration and important research findings that resulted from key international studies on the major pediatric rheumatology diseases.