Anorexia nervosa is a psychiatric disorder characterized by abnormal eating behaviors that results in weight loss and has serious potential medical consequences. Most of these complications are readily treatable if diagnosed and attended to early in the course of the illness. In caring for patients with anorexia nervosa, the primary care physician has several critical roles. Because patients deny the severity of their illness, they delay seeking psychiatric treatment. The primary care physician must be skilled in recognizing this disorder, as well as in diagnosing and effectively treating the medical complications while educating the patient about them. The primary care physician is also involved with arranging and coordinating a comprehensive and multidisciplinary program, including dietary and mental health treatment. The multidisciplinary team is responsible for ensuring safe weight restoration and a judicious refeeding treatment plan. In addition to establishing the diagnosis and treating the multiple medical complications associated with anorexia nervosa, the primary care physician plays a central role in maintaining continuity of care despite the fact that successful care may require a variety of treatment settings. Factors that foster good prognoses for this increasingly common and often protracted eating disorder include early diagnosis and skilled medical intervention to prevent the inexorable physical decline that marked weight loss can cause.