Background: Low back pain is a highly prevalent and disabling musculoskeletal disorder. Physical activity is widely used as a prevention strategy for numerous musculoskeletal disorders; however, there is still conflicting evidence as to whether physical activity is a protective or risk factor for low back pain or whether activity levels differ between people with and without low back pain. Objective: To investigate the association between low back pain and different types (occupational and leisure) and intensities (moderate and vigorous) of physical activity. Methods: This is cross-sectional observational study. We included in this study a total of 1059 individuals recruited from a Spanish twin registry with data available on low back pain. Outcome: Self-reported leisure and occupational physical activity were the explanatory variables. The low back pain outcome used in this study was recurrent low back pain. Results: Our results indicate that leisure physical activity is associated with a lower prevalence of recurrent low back pain. In contrast, occupational physical activity, such as carrying, lifting heavy weight while inclined, awkward postures (e.g. bending, twisting, squatting, and kneeling) are associated with a higher prevalence of recurrent low back pain. There was no statistically significant association between other occupational physical activities, such as sitting or standing, and low back pain. Conclusion: Leisure and occupational physical activity are likely to have an opposed impact on low back pain. While leisure physical activity appears to be protective, occupational physical activity appears to be harmful to low back pain. Future longitudinal studies should assist in formulating guidelines addressing specific types and intensity of physical activity aimed at effectively preventing low back pain.