Fifty adolescents, 12-17 years of age, were treated for obesity from 1967 to 1972. They were contacted in 1977 to obtain follow-up data. Each subject had been treated in a program of dietary counseling and behavior modification. Mean weight on follow-up was 18.1 lb (8.2 kg) lower than mean initial weight (P less than 0.05). The mean decrease over desired weight was 29.5%. Twenty-two patients reported a weight loss of greater than 20 lb (P greater than 0.001). (9.1 kg) and 15 patients reported a weight loss of 0-20 lb (9.1 kg). Thirty-eight percent of the patient were no longer obese (greater than 20% over ideal body weight) and an additional 22% were no longer overweight (10-20% over ideal body weight). These results suggest that a dietary and behavior modification program offered to adolescents may show beneficial results in young adulthood.