The Third International \~orkshop on "The in Vitro Effects of Mineral Dusts" was held on October 1 - 4, 1984 in Schluchsee, Black Forest, Federal Republic of Germany. In six sessions, 93 participants from 14 countries (USA 32, France 17, United Kingdom 12, FRG 11, Canada 9, Belgium 3, Hungary 1, Italy 2, India 1, Nether­ lands 1, Norway 1, Poland 1, Portugal 1, Turkey 1) treated and discussed the following subjects: - Significance of the physico-chemical properties of inhalable mineral dusts (mine dusts, asbestos, Man-Made Mineral Fibres - MMMF). - Cellular effects of inhalable mineral dusts with special regard to target ce 11 s. - Immune response and immune toxicity. - Carcinogenicity and interrelated genotoxic and non-genotoxic effects. - Effect of cell metabolism in combination with inflammation and fibrogenesis. - Significance and credibility of in vitro test systems. For the pathogenesis of biological effects and diseases caused by inhalable mineral dusts a number of factors may be significant such as: - Type of dust - Dose of dust - Size and shape of dust particles, and especially - Surface properties of dust particles, which inter alia determine the - sorption properties, e.g. for environmental substances.