Chronic inflammatory arthritis in childhood could be due to an obvious cause (e.g. sepsis, rheumatic fever, systemic lupus erythematosus etc.), or it could be idiopathic. After excluding those with obvious cause there still remains a large group of chronic inflammatory arthritis in childhood. This category has been variously called 'juvenile rheumatoid arthritis', 'juvenile arthritis', 'juvenile chronic arthritis', and more recently, 'idiopathic arthritis of childhood', The present article reviews the various classification criteria used for defining this group of disorders with emphasis on the common features as well as the major differences between these criteria. The major classes within this group with their characteristic clinical and laboratory features are also discussed.