It was analysed if the weight course in the first half of a four-step psychosomatic treatment program for inpatients with Anorexia nervosa (AN) was useful to predict premature termination of treatment. The weight courses, sociodemographic and disorder-related data of 121 female adult inpatients were investigated. 39% of the studied patients did not reach their target weight (not completers). 61% of the patients completed all four steps of treatment (completers). The not completers showed significant more time with weight losses in the first step and had more and bigger weight losses in the second step of treatment than the completers. Furthermore, they had fewer comorbid depression. In contrast to the sociodemografic and disorder-related data, the weight courses in the first treatment half were very useful to predict premature termination of treatment for inpatients with AN.