The purpose of the project was to compare the effectiveness of three different types of follow-up of a weight control program in assisting adolescent girls to achieve and maintain ideal body weight. During the initial phase of the weight control program, subjects attended two sessions of approximately one hour each for eight weeks. One session each week included theory and practice of physical exercise. The other session was devoted to behavioral control of eating and diet therapy. After eight weeks, 18 subjects were divided randomly into three groups for follow-up: Group 1--monthly measurements and reinforcement of behavioral, diet, and exercise components of the weight control program; Group 2--monthly measurements; and Group 3--annual measurements. Fifteen subjects completed the 12-month follow-up program. Mean weight loss during follow-up of Group 1 was 3.65 kg, Group 2 was 1.90 kg, while Group 3 had a mean weight gain of 3.44 kg. The results suggest that regular follow-up may be a critical element in successful weight control programs for adolescent girls.