Introduction: Thanks to the epidemiological surveillance program for musculoskeletal disorders (MSDs) implemented in the Pays de la Loire region, it was possible to estimate the prevalence of low back pain and exposure to its risk factors among the working population. Method: A sample of 3,710 employees aged 20 to 59 was selected by random sampling between 2002 and 2004. Medical and occupational exposure data were collected via a self-administered questionnaire. Results - The prevalence of low back pain over the past 12 months was high, higher among men (59%) than among women (54%). A high prevalence of daily pain was observed, for men, mainly among white-collar workers and civil service staff and among blue-collar workers, and, for women, among female blue-collar workers. Manual laborers, civilian employees, and public service workers were the occupations most exposed to risk factors for low back pain. Conclusion: This surveillance of musculoskeletal disorders confirms the high prevalence of low back pain and its risk factors among the working population and helps identify the occupations where prevention should be a priority. (R.A.)