Musculoskeletal disorders (MSDs) encompass a range of periarticular conditions affecting the soft tissues (muscles, tendons, nerves, blood vessels, and cartilage) of the limbs and back. Claims for compensation for MSDs are increasing year after year in most Western countries. In France, as in most European Union countries, MSDs have been the leading cause of compensated occupational diseases (CODs) for over five years. In 2002, 21,126 cases of MSDs were recognized under Table 57 of occupational diseases throughout France, representing 67% of compensated occupational diseases (31,461). Little epidemiological data is available to describe the current prevalence of MSDs. For this reason, at the initiative of the French Institute for Public Health Surveillance (InVS), an experimental epidemiological surveillance network for MSDs was established in 2002 in the Pays de la Loire region to provide a statistical description of MSDs and their risk factors. This aligns with the priorities of the European Agency for Safety and Health at Work and will facilitate the planning and monitoring of MSD prevention initiatives (Buckle and Devereux, 1999). One component of this experimental network involves the epidemiological surveillance of carpal tunnel syndrome (CTS), considered a "marker" condition for upper limb MSDs. This CTS surveillance was established in the Maine-et-Loire department in 2002 to estimate its incidence in the general population, study its distribution by sector of activity and occupation, and determine the proportion of cases attributable to occupational factors. (R.A.)