Prediction of the long-term outcome for patients with juvenile idiopathic arthritis requires assessment of disability, psychosocial and socioeconomic function. Measures for the first have evolved from Steinbrocker functional classifications to validated self-administered questionnaires. The proportion of patients with severe disability has decreased during the past three decades but significant numbers of patients enter adulthood with some disability detected with the newer measures. Despite careful study, few early predictors of a poor outcome have been identified. The most consistent are early age at onset, persistent fever and thrombocytosis in patients with systemic juvenile idiopathic arthritis. Reports of psychosocial and socioeconomic outcomes are controversial and further analyses of these spheres are required. An increased risk of osteoporosis and osteopenia has been reported in adults with juvenile idiopathic arthritis. The most significant problem faced by patients during adulthood is persistent disease activity as disability, radiographic damage and the risk of osteoporosis all increase with increasing duration of disease.