Musculoskeletal disorders (MSDs) represent a major occupational health problem in industrialized countries. In 2002 in France, 21,126 cases of MSDs were recognized under Schedule 57 of occupational diseases, accounting for 67% of all compensated occupational diseases. The human cost of MSDs is considerable (pain and discomfort at work and in daily life, sometimes irreversible functional sequelae, risk of job loss, prolonged absences from work), and their impact on business performance is also significant. At the initiative of the French Institute for Public Health Surveillance, an experimental network for the epidemiological surveillance of MSDs was established in 2002 for a three-year period in the Pays de la Loire region. The main objectives of this network are to describe the prevalence of MSDs and their primary occupational 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 prevention initiatives for work-related MSDs. This document describes the general methodology of the component related to the epidemiological surveillance of MSDs in companies in the Pays de la Loire region and reports the results observed during 2002, the first year of the network’s implementation. (R.A.)