Both psychosocial factors and physical factors related to work have been found to be associated with low back pain (LBP) in many cross sectional and some longitudinal studies. [1][2][3][4] In analyses of potential risk factors for LBP related to work, often physical factors only, or psychosocial factors only, have been considered. Less often both types of factors have been studied and analysed simultaneously. 5 Even less often have conditions outside work been studied in parallel with work related conditions.6 Such a parallel approach is necessary for an understanding of the relative significance of diVerent risk factors. One argument for this approach is that, especially among women, a large part of the total daily physical and psychosocial load derives from tasks outside work, 7 as pointed out in a review by Frankenhauser. 8A second argument is that there mightbesides the interaction between work related psychosocial factors which has been demonstrated by Lindström 9 -be an interaction between factors related to work and conditions outside work, especially factors of a psychosocial nature. Such factors might influence each other, as mentioned by both Frankenhauser 8 and Friedman.10 Such reciprocal influence complicates analyses of associations between work related psychosocial risk factors and health outcomes, but increases the need for such analyses.In longitudinal studies psychosocial factors such as job satisfaction, work content, control in the work situation, social relations, and mental overstrain have been found to be associated with LBP. [11][12][13][14][15][16] Physical factors in these studies considered to contribute to LBP are physically heavy work and previous back problems.The aim of the present study was to investigate the relation between psychosocial and physical factors at work, as well as conditions during leisure time, and LBP over 24 years.