Juvenile idiopathic arthritis (JIA) is one of the most common chronic diseases of childhood. The annual incidence in the UK is 1 in 10,000 children and the prevalence is 1 in 1,000. JIA occurs in all races and geographical areas and is more common in girls. The age of onset peaks between three and six and then again around adolescence. As most children with JIA will first present to primary care, GPs have an important role in diagnosis and management.[With external links to the evidence base]