Turnover represents a major problem for nursing and health care in terms of cost, the ability to care for patients and the quality of care given. As a result, turnover has been the subject of a large number of investigations, both in nursing and non-nursing fields. However, many of the articles published report conflicting findings. A further complication is the variety of methodologies researchers have used; there has been little agreement on definition, measurement or reporting strategies. This has led to considerable confusion when attempting to compare studies. This article reviews what is currently understood about nursing turnover from an organizational perspective, and examines some of the methodological considerations surrounding the study of nursing turnover. Historically, nursing turnover research appears to have relied heavily on studies conducted in non-nursing areas for methodological guidance. References to non-nursing studies are therefore important and are reported where appropriate.