The new field of psychoneuroimmunology (PNI) studies the measurable interaction between psychological and physiological processes. Specifically, PNI is the study of the intricate interaction of consciousness (psycho), central nervous system (neuro), and the body's defense against external infection and aberrant cell division (immunology). Over the last 30 years, the body of knowledge in PNI has emerged and in the last 10 years has flourished. PNI has many implications for clinical nursing practice. This study provides supportive empirical evidence to systems theories, which have played a major role in nursing's attempt to comprehend the interaction between the mind and the body. Nurses are ideal candidates to take a lead in this new field because it reinforces the holistic perspective which is the essence and uniqueness of our discipline. Although a variety of clinical populations have been used in PNI research, the scope of this integrated review will be limited to PNI and cancer. Research studies addressing psychosocial variables' effect on aetiology, response to treatment, immunocompetence and overall survival in the oncology population will be examined.