AIM:To explore nurses' understanding and interpretation of evidence-based practice (EBP). BACKGROUND:EBP has been welcomed into the nursing lexicon without a critical examination of its interpretation by practitioners. The literature suggests that there is a great deal of confusion and contradiction over the meaning and application of EBP. Although work has been conducted on how EBP might be implemented, the general issue of how nurses understand and use EBP is largely unexplored. This paper seeks to examine in depth the understandings of EBP, to enable managers, educationalists and policy makers to implement it more effectively. METHODS:All registered nurses, midwives and health visitors in one UK National Health Service (NHS) Trust were asked to complete a questionnaire in October 2006. RESULTS:Despite a disappointing response rate (8.9%, 218/2438), the survey revealed interesting tensions and contradictions in nurses' understanding of EBP. National and local guidelines, practitioners' own experience and patients' preferences were the main influences on nurses' practice. Published research had relatively little impact, particularly among nurses graded E, F and G and those who had not attended a study day on EBP. CONCLUSIONS:The hierarchies of evidence propounded in local and national guidelines are not adopted by practising nurses, who use other sources of evidence, such as reflection on their own experiences, when making clinical decisions. However, subsuming published evidence to clinical judgement does not contradict the original tenets of EBP. IMPLICATIONS FOR NURSING MANAGEMENT:Unless it is incorporated into national or local guidelines, research has relatively little impact on practice. To develop nursing practice and nursing knowledge, nurse leaders need to foster the synthesis of experiential knowledge and published research, in accordance with the founding principles of the EBP movement.