The aim of this 12-month prospective study was to compare reports describing the health-related quality of life (HRQL) of children with Juvenile idiopathic arthritis (JIA) obtained from parents and children, to investigate the extent to which the children's HRQL changed over a 12-month period, and to describe the relationship between children's HRQL, and their experience of pain and use of pain coping strategies. Fifty-four children aged 8-18 years with JIA and their parents completed standard questionnaires assessing children's HRQL, pain intensity, and pain coping strategies at baseline, 6 months, and 12 months. In general, children reported that their HRQL was better than was reported by parents. Both informants described children's HRQL as being very stable over the 12 months of the study. Consistent with the Biobehavioural Model of Pain, there was a significant negative relationship between children's HRQL and their experience of pain. However, there was little evidence that pain coping strategies mediated the relationship between children's experience of pain and their HRQL.