Introduction Low back pain in childhood has been linked with the continuation of such pain into adulthood, and children with LBP at age 14 years are more likely to have LBP a quarter of a century later than those children who are LBP free. It is possible that prevention of this pain in childhood may be conducive to the prevention of LBP in adulthood. Less is understood regarding the aetiology of such pain in younger populations. Most of the epidemiologic research has investigated mechanical factors as possible causative mechanisms. Nevertheless, it is likely that much of childhood LBP is unexplained. The evidence is certainly more sparse relating to the role of psychosocial factors such as the familial aggregation of LBP, emotional and behavioural factors and other somatic complaints as associated symptoms. Emotional and behavioural factors have been found to be more important than mechanical factors in the reporting of childhood headaches and general joint and musculoskeletal pains, hi this scenario LBP may, as in other somatic childhood pain complaints such as headaches and stomach aches, be a manifestation of distress. Aims and objectives The main aims of this thesis are to answer the following questions: (1) What is the prevalence of LBP in a population of British schoolchildren? (2) What is the nature of this LBP in terms of symptom characteristics and (3) What is the role of mechanical and psychosocial factors as possible causative mechanisms in LBP in schoolchildren? Conclusions The current study has confirmed that LBP is common in schoolchildren and has a marked impact on daily life although it is unlikely to lead them to seek health care. The findings also demonstrated that psychosocial rather than mechanical factors are important in the reporting of LBP in children. Further, LBP is most common amongst children reporting other frequent childhood symptoms. Due to the cross-sectional design of this study, the temporal relationship between both mechanical and psychosocial factors in LBP in children remains unclear highlighting the need for long-term follow-up studies in this population.