Psychotherapy and psycho-social interventions in oncological rehabilitation, based on confirmed results of several controlled studies designed and conducted in a bio-psycho-social research framework, have been proved to reduce the psycho-social vulnerability of cancer patients and to enhance health related quality of life in this patient population. It is also supposed that psychological intervention increases survival outcomes of cancer patients through immune-modulation. Findings of psycho-neuro-immunological research have underlined that the human neurological and immunological system, mainly the NK, CD4 and CD8 cell activity and cytotoxicity, are mediators and modulators in the progress of malignant tumors. Positive outcomes of psycho-social rehabilitation in oncology reinforce not only its effectiveness in reducing stress and anxiety, strengthening active coping mechanisms and immune functions, and improving quality of life but also its cost-effectiveness in view of relatively low investment and the high, multiplied health related benefits.