Six female patients with anorexia nervosa, who met the criteria shown by Halmi et al. or Suematsu, were treated by dietary therapies with behavioral modification and no medication, being compared with another six female patients treated by psychiatric counsel alone. Their lives in the hospital were restricted and isolated from their own families and relatives for the early period of admission, in which psychiatric counsels were regularly performed. In dietary therapy the meal contained 1200kcal per day for the first time and was gradually added by 200kcal per day at an interval of 7 to 14 days as the patients could eat completely. However, in patients who were severely undernourished and showed no desirable eating attitude nor modest weight gain, they were further given a nutrient such as “Sustagen” (200-400kcal per day) between meals. The gain of mean weight from 32kg to 42kg was found within a year by such diet therapies, while by psychiatric counsel alone that from 32kg to 45kg was visible within several years. It is concluded that these dietary therapies with behavioral modification may be useful to facilitate the patient's return to a regular eating attitude and ideal body weight.