AbstractWorldwide, psychological and social issues in cancer were not the subject of scientific inquiry until the past two decades. Since then, a new subspecialty of oncology has evolved, psycho‐oncology. It addresses two dimensions of cancer: the emotional responses of patients at all stages of disease, as well as their families and caretakers (psychosocial); and the pyschological, social and behavioral factors that may influence cancer morbidity and mortality (psychobiological). Obstacles to development have been the facts of small numbers of clinicians and investigators worldwide and the few valid assessment instruments and research methods available to the biomedical community. These obstacles are increasingly giving way to the louder demand of the public for maximal quality of life in cancer care. Psycho‐oncology is attaining subspeciality status by presently bringing a set of clinical skills in counseling, behavioral and social interventions to oncology, by providing training curricula which teach basic knowledge and skills in the area, and through creating a body of research and scholarly information about clinically relevant issues in the care of patients with cancer. Since it is increasingly recognized that psychological, social and behavioral variables influence treatment outcome, attention will likely to continue to increase. The field must meet the challenges of the 1990's in psychosocial care and availability of services, support for training clinicians and investigators in psycho‐oncology, and implementation of an exciting research agenda. The focus of new research will encourage collaborative investigations combining biological and psychosocial variables, quality of life research in clinical trials, controlled studies of psychotherapeutic, behavioral and psychopharmacologic research, and crosscultural studies that will examine differences in prevention and detection, health care systems, alternative therapies and meta ana