A behaviour therapeutic program for weight reduction was worked out by a team of psychologists, dieticians and doctors. A 10 week's course for weight reduction was given by 8 dieticians to a group of 5-7 female overweights (N=50). All dieticians based their work on a written handout. 4 of them had an additional training in behaviour and group therapy prior to the course. During the course all participants showed a significant weight loss and a change in their eating behaviour, the patients counselled by an additionally trained dietician (group E1) showing a significantly greater weight loss than the others (group E2). A follow-up after 3 1/2 months revealed similar differences but subsequent controls after 6 and 20 months showed a gradual decrease of the difference between the two groups. However three different patterns of the patient's weight curve could be distinguished. Pattern a): 26.3% of the participants showed a sinking tendency over all 20 months. Pattern b): 21.4% of the participants showed a significant weight loss over the 20 months with a slight upward tendency after the second follow-up (6 months). Pattern c): 52.3% of the participants lost weight only during the course which was regained in the following 3 months period. In pattern a) and c) group E1 and E2 are evenly represented. Pattern b) was only seen with participants of group E1. The results suggest that there are different characteristics of obese persons which influence the success of weight reduction programs. Further studies will have to describe these characteristics and define their therapeutical implications.