Objectives: To describe the disease characteristics, continuous course and long-term outcome and to evaluate predictors of outcome in JIA in Greece.Methods: We performed a retrospective cohort analysis of 17 years' prospective data on JIA. Outcome assessment included radiographic (modified Sharp-van der Heidje score), articular and extra-articular damage (Juvenile Arthritis Damage Index), functional ability (HAQ Disability Index), and the cumulative percentage time spent in a state of active disease and also in clinical remission off medication (CR) (according to Wallace's criteria).Results: One hundred and two (72 females) patients under regular follow-up were enrolled. The disease age of onset [mean (SD)] was 7.7 (4) years, the interval from onset to last visit was 17.2 (6.7) years and the patients' current age was 25 (5.9) years. At the last follow-up visit, 53 patients (52%) had disease activity, while 23.5% were in CR. The cumulative percentage time spent in a state of active disease and CR over the disease course was 52.6 and 17.8%, respectively. Polyarticular subtype of onset and longer disease activity during the first 5 years were independent predictors of worse outcome. Additional telephone-based interviews of 205 former JIA patients who had been lost to follow-up as adults were performed to extend the interpretation of our findings to a broader JIA population. Almost half (47.6%) of the total cohort of 307 patients were found to be in CR at the final evaluation and 69.7% had no disability.Conclusion: The available data indicate that JIA as a whole is a heterogeneous disease with significant variability in course and long-term outcome.