BACKGROUND: Obesity has adverse physical, social, and economic consequences that can negatively affect quality of life (QOL). Thus the aim of this study was to verify the effects of a long-term multidisciplinary lifestyle intervention on QOL, body image, anxiety, depression and binge eating in obese adolescents. METHODS: Sixty-six obese adolescents (41 girls and 25 boys; BMI: 35.62 +/- 4.18 kg/m2) were recruited from the Multidisciplinary Obesity Intervention Program outpatient clinic, and were submitted to a multidisciplinary lifestyle therapy (short-term = 12 weeks and long-term = 24 weeks), composed of medical, dietary, exercise and psychological programs. Validated self-report questionnaires were used to assess symptoms of anxiety Trait/State (STAI); depression (BDI); binge eating (BES), body image dissatisfaction (BSQ) and QOL (SF-36). Data were analyzed by means of scores; comparisons were made by ANOVA for repeated measures, and Turkey's test as post-hoc and Students T test. RESULTS: Long-term therapy decreased depression and binge eating symptoms, body image dissatisfaction, and improved QOL in girls, whereas, for boys, 24 weeks, were effective to reduce anxiety trait/state and symptoms of binge eating, and to improve means of dimensions of QOL (p < .05). CONCLUSION: A long-term multidisciplinary lifestyle therapy is effective to control psychological aspects and to improve QOL in obese adolescents.