Prognostic factors in juvenile arthritis are related to many variables that must be evaluated according to the different subtypes. The International League of Associations of Rheumatologists (ILAR) recently proposed six different categories referred to as the Durban criteria, under the eponym of juvenile idiopathic arthritis (JIA). The aim of this classification was to define homogeneous groups according to their clinical and biologic features. The prognostic factors were classified into the different categories of JIA. A poor outcome in the systemic form correlated with markers of disease activity, such as fever and polyarticular involvement, within the first 6 months. The risk of joint destruction in oligoarthritis correlated with the severity of arthritis within the first 2 years. Polyarthritis with positive rheumatoid factor is associated with marked disability in adulthood. In a group of psoriatic patients, the risk of developing sacroiliitis is higher in male and HLA-B27-positive patients. Patients with enthesitis-related arthritis with lower limb, knee, and tarsal involvement also are at greater risk of developing sacroiliitis. Chronic uveitis is a complication of JIA observed mainly in patients with oligoarthritis associated with positive antinuclear antibodies in serum. Secondary amyloidosis is observed mainly in children with systemic JIA. The long-term outcome must be discussed according to the various therapies. Corticosteroids contribute to growth retardation and osteoporosis, for which the use of human recombinant growth hormone and biphosphonates may be an option. Newer encouraging therapies such as anticytokines have been proposed for children with active disease. Autologous stem cell transplantation is being evaluated in some centers with promising results; however, it has a high rate of mortality. Further discussion regarding which patients should undergo autologous stem cell transplantation is needed, as is further discussion regarding the technical adaptations necessary.