Major public health problems such as cardiovascular disease and type 2 diabetes pose a challenge to both the medical profession and the health care system of most Western countries. In spite of widespread knowledge about risk factors and pathophysiological processes, it has been difficult to find effective preventive mass strategies based on evidence from controlled clinical trials. In the Malmö Preventive Project, Sweden, 33 346 subjects were screened for risk factors between 1974 and 1992, and a quarter of them were offered preventive help for cardiovascular disease risk or alcohol abuse. The overall finding of the project was that benefits of screening and prevention on mortality risk could only be shown in certain subgroups of younger men and women, not in the total screened cohort, as compared with a nonscreened reference population. These findings therefore question the effectiveness of preventive methods and drugs used during previous decades. New preventive methods are therefore needed and should be properly evaluated to form a basis for evidence-based prevention (EBP) in cardiovascular medicine.