Anorexia nervosa (AN) is a relatively common disorder, especially in adolescent and young adult women. The lifetime prevalence of AN in females ranges from 1.2 to 2.2%. The prevalence in males is 10-times lower. The condition is associated with a high risk of chronic course and poor prognosis in terms of treatment and the risk of death. Longer follow-up periods seemed to correspond with increased improvement rates and increased mortality. Onset of the disorder during adolescence is associated with better prognosis. It is reported that as much as 70% to over 80% of patients in this age group achieve remission. Worse outcomes are observed in patients who required hospitalization and in adults. Recent studies indicate improved prognosis for cure and lower mortality rates than previously reported. However, the recovery can take several years and AN is associated with high risk of developing other psychiatric disorders during the patients’ lifetime, even after recovery from AN (mainly: affective disorders, anxiety disorders, obsessive-compulsive disorders, substance abuse disorders). Studies indicate that bulimic symptoms often occur in the course of anorexia nervosa (especially within 2–3 years from the onset of AN). The authors present a review of literature on the course, comorbidity, mortality, and prognostic factors in AN. Better knowledge of the course of anorexia can contribute to more realistic expectations of the pace of symptomatic improvement, as well as to a creation of therapeutic programs which are better adapted to the needs of the patients.