Occupational diseases (ODs) encompass any illness or symptom that occupational physicians, based on their expertise, deem to be related to work and that is not covered by a social security program. As a result, they are not included in the annual social security statistics. In 2003, an OHD surveillance program was launched in the Pays de la Loire region by the Occupational Health Department of the French Institute for Public Health Surveillance (InVS) and the Occupational Health Inspection Unit of the Regional Directorate for Enterprises, Competition, Consumer Affairs, Labor, and Employment (Direccte). The program has since expanded to 13 regions. Each year, data from these regions are compiled to provide national surveillance data, and the results for each region are shared with local stakeholders. This brochure presents the main results of the 14th and 15th MCP two-week periods in the Pays de la Loire region, which took place in 2011 (from June 27 to July 8, 2011, and then from November 28 to December 8, 2011).