This paper explores the relationship between the life sciences of anatomy, physiology, microbiology and pharmacology and the teaching/learning problems of their application in nursing. A theoretical model is proposed derived from a conceptual consideration of nursing tasks and of nursing actions developed to account for a direct link between these sciences and nursing. It is argued that a ‘bio-nursing'approach to the use of the life sciences in nursing is comparable to that of a ‘bio-medical’ approach in medical education and practice. The paper suggests lhat an appropriate examination of the contributions of the life sciences to nursing education will provide a more concentrated and illuminating exercise with regard to making possible the identification of a body of knowledge of direct relevance to nursing practice. The teaching/learning implications for nurse education and the development of a distinctive knowledge base derived from these sciences are discussed.