Obesity is one of the most common conditions encountered by primary care physicians, yet both physicians and patients are often frustrated by current approaches to its management. Recent advances in our understanding of obesity enable the physician to evaluate the contributions of biologic and environmental factors to the patient's obesity, to determine the degree of medical risk posed by the obesity, and to establish realistic goals for treatment. The chronic and relapsing nature of obesity requires ongoing support and vigilance. An individualized approach to obesity management, based on careful evaluation of biologic, psychologic, and social factors, can be successfully developed and implemented by the office-based primary care physician.