Surveillance of Mycobacterium tuberculosis resistance to antituberculosis drugs in France has been conducted since 1995 by a group of microbiologists from university hospitals, the Azay-Mycobacteria Group (Azay), in collaboration with the National Reference Center for Mycobacterial Resistance to Antituberculosis Drugs (CNR-RMA). For each culture-positive (C+) case, microbiologists collect the information recommended by the World Health Organization (WHO): age, sex, country of birth, HIV co-infection, site of tuberculosis, prior anti-tuberculosis treatment, results of the microscopic examination, and results of anti-tuberculosis drug susceptibility testing. After analysis, these data are transmitted to EuroTB, the European tuberculosis surveillance program, and to the WHO. The objective of the Azay-Mycobacteria network is to describe the prevalence of M. tuberculosis resistance to first-line antituberculosis drugs in new cases (“primary resistance”) and previously treated cases (“secondary resistance”). The network relies on volunteer microbiologists because the data are not routinely collected by most microbiology laboratories. In 2002, the network covered 18 regions of metropolitan France. The objective of this study is to evaluate the quality of data collected by the Azay-Mycobacteria Network’s voluntary surveillance system—excluding resistance data assessed through quality control of antibiotic susceptibility testing—by comparing it to the reference standard provided by the system for notifiable diseases (DO). This retrospective analysis was conducted in 2003–2004 in collaboration with the CNR-RMA, physicians responsible for managing DO reporting in three Departmental Directorates of Health and Social Affairs (DDASS) in the Île-de-France region, a physician responsible for tuberculosis control, the Azay-Mycobacteria group, and the French Institute for Public Health Surveillance (InVS). (Introduction)