Low back pain in adolescents is perceived to be uncommon in the clinic setting. However, previous studies have suggested that it may be an important and increasing problem in this age-group. The aim of this study was to determine the prevalence and important symptom characteristics of low back pain such as duration, periodicity, intensity, disability and health seeking behaviour at young ages. A population-based cross-sectional study was conducted including 1446 children aged 11-14 years in the North-West of England. A self-complete questionnaire was used to assess low back pain prevalence, symptom characteristics, associated disability and health seeking behaviour. An additional self-complete questionnaire amongst parents sought to validate pain reporting. The 1-month period prevalence of low back pain was 24%. It was higher in girls than boys (29 vs. 19%; 2=14.7, P<0.001) and increased with age in both sexes (P<0.001). Of those reporting low back pain, 94% experienced some disability, with the most common reports being of difficulty carrying school bags. Despite this high rate of disability, few sought medical attention. Adolescent low back pain is common although medical attention is rarely sought. Such symptoms in childhood, particularly as they are so common, may have important consequences for chronic low back pain in adulthood.