The Childhood Arthritis Prospective Study (CAPS) is funded by Versus Arthritis and recruits children and young people newly diagnosed with arthritis. CAPS is a national study with its main base at the University of Manchester. We began recruiting in 2001 and have recruited over 1700 patients to date. The aims of the study are to find those things that may help predict how patients will manage over the long-term. Better understanding of the course of the illness will help in choosing the best treatment for children and young people now and in the future.