Eating disorders, particularly anorexia nervosa and bulimia nervosa, are significant causes of morbidity and mortality among adolescent females and young women. Eating disorders are associated with devastating medical and psychologic consequences, including death, osteoporosis, growth delay, and developmental delay. Prompt diagnosis is linked to better outcomes. A good medical history is the most powerful tool. Simple screening questions, such as "Do you think you should be dieting?" can be integrated into routine visits. Physical findings such as low body mass index, amenorrhea, bradycardia, gastrointestinal disturbances, skin changes, and changes in dentition can help detect eating disorders. Laboratory studies can help diagnose these conditions and exclude underlying medical conditions. The family physician can play an important role in diagnosing these illnesses and can coordinate the multidisciplinary team of psychiatrists, nutritionists, and other professionals to successfully treat patients with eating disorders.