The most prevalent form of arthritis in children is Juvenile Rheumatoid Arthritis (JRA), a disorder of the immune system that affects as many as 100,000 children in the United States alone. The three main types of JRA are pauciarticular JRA, which affects only a few joints and may cause eye inflammation; polyarticular JRA, which affects many joints, and systemic JRA, which affects many body parts, including internal organs and joints. While permanent damage to joints is less common in children than in adults, JRA can cause growth problems and joint inflammation and damage. Early diagnosis and treatment is important to control inflammation, relieve pain, prevent and control joint damage, and help young patients maintain their functional abilities.