Psycho-Oncology is the union of Psychology and Oncology, aimed at multidisciplinary care in cancer centres, providing better acceptance of the diagnosis and helping throughout the treatment process and supporting patients in the devastating and often mutilating situations that treatment causes. Psychologists play an important role in the treatment of women with breast cancer, especially in surgical procedures where total removal of the breast is unavoidable. The aim of this project is to describe and discuss the importance of Psycho-Oncology in the oncological treatment process and its work with breast cancer patients. The results of the project suggest that psychological factors can influence the way in which women with breast cancer find it difficult to accept the diagnosis and the changes taking place in their bodies. This points to the importance of psychotherapeutic counselling, together with medical care.