The average prevalence of obesity in Europe is now 15-20%, with the rate in most countries increasing. The prevalence of overweight and obesity combined is as high as 50-65%. Also, childhood obesity is increasing at an alarming rate. The epidemic has been accompanied by a simultaneous rise in type 2 diabetes. Action is therefore urgently needed. This was stressed at an EU conference on obesity in September 2002 in Copenhagen. We must change both the environment and our behaviour to increase leisure-time physical activity and decrease the intake of fatrich, energy-dense foods and drinks, for instance, through improved traffic planning, more physical activity in schools, differential taxes on foods and drinks and the banning of commercials for unhealthy foods. Prevention of overweight in children should be given high priority. There is an urgent need for public health programmes, training of health professionals and collaboration with the food industry.