Occupational diseases (ODs) encompass all illnesses that physicians—and occupational physicians in particular—deem, based on their expertise, to be related to professional activity and that are not covered by the Social Security system. As a result, they are not included in the Social Security’s annual statistics. As part of their missions to conduct epidemiological surveillance of occupational risks, the French Institute for Public Health Surveillance (InVS) and the Occupational Health Inspection (IMT) of the Ministry of Labor have therefore established a system for the epidemiological surveillance of ODDs. This program, launched in 2003, covered 15 French regions by 2012. In Brittany, the program has been jointly conducted since 2012 by the InVS, the IMT of the Regional Directorate for Enterprises, Competition, Consumer Affairs, Labor, and Employment (Direccte) of Brittany, and the Regional Health Observatory (ORS) of Brittany. This first brochure published in Brittany presents the results of the two “Fortnight” campaigns carried out in the region during 2012.