F or the physician evaluating patients who have had occupational exposure to asbestos, two issues having compensation and other legal ramifications, as well as health implications, are likely to arise. First involves the question regarding what action should be taken in the currently employed asbestosexposed worker with early but definite fibrogenic effects on the lungs and/or pleural surfaces, and secondly, under what circumstances does present knowledge allow us to make the determination that lung cancer in an asbestos-exposed individual can be attributed to that occupational exposure? In the discussion that follows, I shall attempt to provide a link between epidemiologic evidence obtained by our group and others, and the clinical determination responsive to these questions.