In this report population-attributable risks (PARs) are reported, which quantify the contribution of several determinants (lifestyle factors such as smoking, alcohol consumption, physical activity and dietary factors, as well as biological risk factors such as total serum cholesterol, HDL-cholesterol, blood pressure, glucose tolerance and body mass index) to mortality from a number of chronic diseases (coronary heart disease, stroke, COPD, diabetes and some forms of cancer). Relative risks and prevalences of risk factors are needed for calculations of PAR's. Relative risks were taken from the international literature and risk factor prevalences (mainly for the age range 20-59 years) were derived from the 1987-1991 Dutch Monitoring Project on Cardiovascular Disease Risk Factors. Some important assumptions and difficulties in calculating and interpreting the PAR's and PAR like measures are summarized in chapter 2. Chapter 3 contains a description of PAR calculations for a series of determinants, later summarized (chapter 4) from the viewpoints of both diseases and determinants. PAR's for individual determinants ranged from 10 to 90 percent. From a Public Health point of view, intervention in a determinant which has a moderately strong influence one or more frequently occurring diseases, will lead to more gain in health than intervention in a determinant which has a strong influence on a rare disease. From the results it is clear, that cigarette smoking is the determinant causing the greatest health loss: the prevalence of cigarette smoking is still high (about 40 percent in men and women aged 20-59 years) in the Netherlands. Cigarette smoking influences mortality from a number of indicators (cancer of the lung, larynx, oral cavity and oesophagus, coronary heart disease, stroke and chronic respiratory disorders). Coronary heart disease has the largest number of determinants for which it was possible to calculate PARs. The general conclusion is that for the health problems mentioned in the Netherlands a substantial health gain is at least theoretically possible. As a large part of these risk factors are made up of life style factors there are important individual and collective choices involved in trying to further improve the health status of the Netherlands. The PARs calculated here for the individual determinants are a simplification of reality, because interactions between determinants have not been taken into consideration. Mathematical models are now being constructed which take these interactions into account. In addition, more attention will have to be paid to the health gains that may be achieved in old age.