OBJECTIVE: To study self-reported pain early in the disease course of juvenile idiopathic arthritis (JIA) as predictor of long-term disease outcomes. METHODS: Consecutive cases of JIA with disease onset 1997-2000 from defined geographical areas of Norway, Sweden, Finland and Denmark were prospectively enrolled in this population-based cohort study. Self-reported, disease-related pain was measured on a 10 cm visual analogue scale (VAS pain). Inclusion criteria were a baseline visit with pain score six months after disease onset, followed by an eight-year study visit. Remission was defined according to Wallace preliminary criteria. Functional disability was measured by Childhood Health Assessment Questionnaire (CHAQ) and Child Health Questionnaire (CHQ-PF50) if age <18 and Health Assessment Questionnaire (HAQ) if age >/=18 years. Damage was scored using the Juvenile Arthritis Damage Index (JADI). RESULTS: The final study cohort consisted of 243 participants, and 120 (49%) had oligoarticular onset. At baseline 76% reported VAS pain >0 compared to 57% at eight-year. Half of those who reported baseline pain also reported pain at eight-year, but at a lower intensity. Compared to no pain, higher pain intensity at baseline predicted more pain at eight-year, more functional disability, more damage and less remission off medication. Baseline pain predicted more use of DMARDs/biologics during the disease course. Participants with oligoarticular JIA reporting pain at baseline were more likely to develop extended oligoarticular or other unfavorable JIA categories. CONCLUSION: Early self-reported, disease-related pain among children and adolescents with JIA is common and seems to predict persistent pain and unfavorable long-term disease outcomes. This article is protected by copyright. All rights reserved.