Approximate estimates have been made of the effect by the year 2005 of various preventive measures to reduce cancer mortality in Scandinavia. Figures have been calculated for changes in smoking, diet and exposure to sunlight (primary prevention), for earlier diagnosis (secondary prevention), and improved survival as a result of improved treatment (tertiary prevention). The calculations have been performed with the American program CAN TROL, the effect being expressed as the percentage reduction in cancer mortality by the year 2005. The results give promise of a substantial overall reduction in cancer mortality in Scandinavia.