Abstract: The Swiss Federal Office of Public Health commissioned the Winterthur Institute of Health Economics and the Institute of Economic Research of the University of Neuchatel to undertake an economic evaluation of disease and accident prevention measures in Switzerland. The main objective of the study was the calculation of the economic return in the three prevention fields of tobacco, harmful use of alcohol, and road accidents with a common methodology. The main questions addressed with regard to prevention measures were: Do these measures work? And, if so, are they worth the money they cost? The main result is a positive return for every franc invested in health promotion and efforts for preventing road accidents, tobacco consumption and alcohol harmful use. The estimated return on investment varies between 9.4 for public road accident prevention programmes, 23 for alcohol prevention and 41 for tobacco prevention. The research has demonstrated the potential benefits of prevention measures; such efforts can deliver good value for money for society as a whole.