Low back pain (LBP) is common in children but the prognostic indicators are poorly understood. We report the results of a prospective study to determine the risk factors for chronic LBP in children. A total of 330 children with LBP were identified from a cross-sectional survey in schools in Northwest England. Data were collected by self-completion questionnaire on a number of potential risk factors for LBP persistence, including lifestyle factors, the occurrence of other symptoms, behavioral and emotional characteristics, and symptom severity and duration. Participants were then followed over the following 4 years to determine persistent symptoms. Complete followup data were available from 178 children, of whom 46 (26%) reported persistent LBP. Forward stepwise Poisson regression identified 5 independent predictors of pain persistence: peer relationship problems, being of smaller stature, the prior report of widespread body pain, long duration of LBP episodes, and radiating leg pain. Of children with none of these factors at baseline, <5% went on to report persistent LBP. In contrast, of those with 4 or 5 factors, nearly 80% experienced persistent symptoms. Although childhood consultations for LBP are infrequent, we have shown that approximately 25% of children 11-14 years of age with LBP still report symptoms 4 years later. These children can be identified early by a combination of clinical markers and etiologic factors. This provides a basis for considering interventions for secondary prevention; the challenge will be to determine whether we can intervene to alter symptom trajectory at an early stage.