A variety of diseases are encompassed in the didactic denomination of granulomatous diseases of probable occupational etiology. As well as presenting similar clinical aspects, such diseases are characterized by certain common traits: formation of granulomas; systemic and respiratory manifestations; environmental or occupational exposure to organic or inorganic agents; and T lymphocyte involvement in the pathogenesis. Included in this category are hypersensitivity pneumonitis, mycobacteriosis (all forms) and sarcoidosis, as well as beryllium disease and other lung diseases caused by exposure to heavy metals. In order to highlight the risk of developing one of these diseases as a result of environmental or occupational exposure to etiologic agents, we address aspects related to epidemiology, pathogenesis and evaluation of exposure of these diseases, as well as those related to diagnostic criteria, prevention and control. We have given special emphasis to groups of individuals considered to be at high risk for developing these diseases, as well as to the need for health care professionals to remain aware of the potential occupational etiology of such diseases, a decisive factor in devising effective measures of prevention and epidemiological surveillance.32 Suppl 2S69-84