This chapter discusses the behavioral treatment of obesity, including its short- and long-term results and approaches to improve long-term weight management, and also explores obesity outcomes and treatment recommendations for ethnic-minority populations. Lifestyle modification includes three principal components: diet, physical activity, and behavior therapy. Three components of behavioral treatment, namely self-monitoring, cognitive restructuring, and stimulus control, are covered. Additionally, the chapter briefly reports the use of more structured or restrictive diets that have been used to induce larger initial weight losses. Long-term patient–provider contact can be obtained in several ways, including on-site visits, telephone, Internet, and e-mail contact. It is shown that behavioral treatment is effective in inducing weight loss and improving health-related complications of obesity.