Anorexia nervosa differs distinctly from other psychogenic eating disorders. Well known for the past 300 years, anorexia occurs consistently and is one of the most serious illnesses to be found for a certain age group. Three-quarters of the patients are healed or improve their condition long-term; one-quarter has a chronic course frequently including somatic complications and death. Because of the long healing process as well as the extensive chronification and complication rate, an individual treatment plan should be set up at the beginning of therapy to allow for a long-term structure of the course of therapy. Depending on the severity, phase and co-morbidity, inpatient and ambulant therapies are indicated. Depending on the duration of therapy, adequate weight (BMI > 15 kg/m2), good motivation, and lack of complications, an ambulant therapy is justified. Inpatient treatment is multimodal corresponding to the multifactorial etiology of anorexia nervosa. Weight gain is an important primary goal of therapy and a prerequisite for a conflict oriented, ambulant psychotherapy to be carried on after inpatient treatment. Ambivalent psychotherapy motivation and the necessity of symptom orientation demand technical modification both for inpatient as well as ambulant psychotherapy.