Psycho-oncology is a relatively new subspecialty of oncology with multidisciplinary interest concerning the psychological, social, behavioral and ethical aspects of cancer, which covers everything from management of psychological problems of cancer patients and long survivors, and palliative and supportive care, to the health care system, with special attention to ethical and spiritual issues. It addresses two dimensions of cancer; the psychological responses of patients to cancer at all stages of the disease, as well as their families and healthcare providers, and the psychological factors that may influence the cancer process. The current concepts of psycho-oncology are overviewed with emphasis on its historical background, clinical significance and the empirical research activities such as quality of life studies in clinical settings and psychoneuroimmunological intervention studies. Humanistic dimensions and future directions of psycho-oncology are discussed with reference to the topics discussed at the International Congress of Psychosocial Oncology in 1992.