Obesity, defined as a body mass index > 30 kg/m2 is relatively common in Europe especially among women and especially in Southern and Eastern European countries. Among men the distribution of body mass index values is surprisingly similar in most countries of Europe despite a large variability among women. Available data from European countries (Germany, Finland, Sweden, The Netherlands, England) suggest that the prevalence of obesity has been stable or (most often) increasing during the ninety-eighties. Publications from affluent countries outside Europe suggest similar trends. These trends suggest that public health policies recommending avoidance of overweight and the common practice of dieting fail to prevent an increase in the prevalence of obesity, let alone to reduce the prevalence. It is unclear which factors are responsible for weight gains in Europe. Continuing high fat intakes in combination with low physical activity and widespread cessation of smoking may contribute to the increasing prevalence although some studies suggest that increased prevalences are also found in smokers and non-smokers. Obesity as well as weight gain are both important and independent contributors to cardiovascular disease and diabetes mellitus. More research is needed to elucidate the reasons for the large variation in the prevalence of obesity among European women and to the health risks associated with obesity in different European countries.