The behavioral treatment of obesity consists of a set of principles and techniques to help overweight individuals modify inappropriate eating and activity habits. As provided in University and hospital clinics, this approach produces an average loss of 8.5 kg (9% of initial weight) in approximately 20 weeks. The maintenance of weight loss is facilitated by the provision of long-term patient-provider contact as well as by the use of weight-loss medications. The most promising results are likely to be obtained when behavioral and pharmacologic approaches are combined. The article concludes with a discussion of the importance of treating obese individuals with respect and compassion.