Background: The homeless are at very high risk for both respiratory diseases and poor access to health care delivery systems. The aim of this study was to assess the contribution of a shelter-based survey to identify respiratory diseases in the homeless population in Marseilles, in order to further develop preventive interventions. Methods: A prevalence survey of respiratory diseases was conducted in two homeless shelters in Marseilles, in February 2005. A multidisciplinary team including infectious diseases specialists, lung specialists, residents, nurses, physiotherapists and X-ray technicians visited the two shelters. Interview, physical examination, sputum sampling for Mycobacterium tuberculosis detection, nasal swabs for virus detectio...