Obesity is associated with an increased somatic morbidity and mortality. This paper focuses on the controversial issue of mental co-morbidity in various populations of overweight and obese persons and the relationship to the utilization of medical care and health behaviour. Therefore, this paper focuses on health care utilization and health behaviour in overweight/obese with mental co-morbidity. In a representative German community sample with n=1281 we administered valid self-rating scales on depression and anxiety. Using established cut-off scores we identified 61 subjects with both overweight/obesity and at least one mental disorder. Compared to the overweight/obese without mental co-morbidity, those subjects showed a more extensive health care utilization of psychiatric and psychotherapeutic services and reported more smoking. Beside the number of somatic problems, age, BMI, female gender and residence in Eastern-Germany a lower subjective health in overweight/obese subjects could be predicted by the occurrence of at least one mental disorder. Our results implicate the need to focus on psychotherapy in weight reduction programmes for participants with mental co-morbidity.