Introduction. Studies on the prevalence of back pain are rare both in the general population and among workers. Thanks to the epidemiological surveillance program for musculoskeletal disorders (MSDs) implemented in the Pays de la Loire region, it has been possible to estimate the prevalence of back pain among the working population. Method. A representative sample of 3,710 employees aged 20 to 59 was selected by occupational physicians through random sampling between 2002 and 2005. Medical and occupational data were collected via a self-administered questionnaire. Results. The prevalence of back pain was higher among women (17.4%) than among men (9.2%), with no difference by age. Among men, employees reported back pain more often (16.6%) than workers in other socio-professional categories (managers: 7.1%, intermediate professions: 6.5%, manual workers: 9.7%). Among women, managers tended to report back pain more frequently. There was no significant difference in the prevalence of back pain by industry sector, among both men and women. Conclusion. The prevalence of back pain, while lower than that of low back pain, is nevertheless significant in certain occupational categories. (R.A.)