Prevention of obesity should have the highest priority and be started as early in life as possible in high-risk families. This review covers the most promising areas of today’s research aimed at finding better ways of treating obesity in the future and an overview of the treatment choices available at present. The cause of obesity is genetic in approximately 40–50% of adults and probably a larger proportion of children. This means that it is possible to remain overweight without a higher calorie intake than that of individuals of normal weight who lack the genetic susceptibility to obesity. Treatment is recommended from 10 years of age with a slightly hypocaloric diet (1500 kcal) and a reduced fat content (30 energy-percent). Exercise is often provided naturally by the child before this age. It is helpful to try to replace aspects of our sedentary life-style, including televiewing, with moderate physical activities, such as walking. Family therapy has been effective in introducing these changes in life-style. Other strategies, such as behavioral therapy, have also been tried, individually, in groups, or at school. Cognitive therapy has no advantage over behavioral therapy in childhood obesity. No reports on psychodynamic therapy have been published. Surgery is used only in the case of rare inborn metabolic diseases. Thus, further development of obesity therapy is needed, although the treatment of children seems to give better results than treating adults.