The aim of this formative evaluation (action research) study was to develop and apply a set of criteria for benchmarking evidence-based nursing. There were three phases: the identification (through literature searches and contact with experts) of previous work on the development and assessment of evidence-based nursing; the development (through a consultation exercise) of criteria for measuring and benchmarking evidence-based nursing; and applying these criteria (through semi-structured interviews) in six discrete clinical areas. Numerous papers were found that discussed evidence-based nursing and barriers to research utilisation, but no previous work on benchmarking or assessing evidence-based nursing was found. Fourteen 'benchmarking evidence-based nursing' criteria were developed, organised around four key themes for achieving effective practice: Selecting a particular aspect of practice to question or examine; finding out from the literature, professional networks and other sources what is current best practice, and critically appraising the available literature and sources of information; implementing and/or learning how to provide best-known clinical practice; and confirming that you are providing best practice. All six clinical areas were generally poor on all 14 benchmarking criteria. However, there were some positive attributes: nurses with degree level post-registration education had better knowledge of searching for and critically appraising research; some senior clinical specialists were supportive of evidence-based changes; and one ward had stronger communication/dissemination links for relevant evidence with related clinical areas (paediatrics). It was concluded that the benchmarking tool developed in the study was useful in identifying positive and negative aspects of evidence-based nursing practice. The tool may be helpful to other organizations considering how to take forward evidence-based nursing practice.