Physical exercise does not only have positive effects on physical fitness but also on mental health. However, there has been little empirical study on effects of rehabilitation programmes based on physical exercise in cancer patients. We conducted a study to examine the interrelation between the participation of breast cancer patients in an exercise rehabilitation training and aspects of quality of life and physical fitness. 28 patients with not metastasized mamma carcinoma participated in a structured exercise rehabilitation program twice a week for ten weeks. Before and after the intervention the patients were asked to fill in questionnaires to assess their quality of life. At the same instants they underwent physical examination and a bicycle ergometry as well as a blood drawing. The training was aimed at changes at the social, emotional, as well as the motor physical level. Pre-post comparisons demonstrated an improvement in quality of life, such as decreased levels of depression and anxiety. Furthermore the women proved to show an obvious increase in physical fitness. Present results support an implementation of an exercise rehabilitation training for breast cancer outpatients.