Organisational culture is presented as a complex concept underpinned by specific values, beliefs and assumptions that account for the way things are done. Strong organisational cultures and a number of other attributes are highlighted as having influence on performance. The role of leadership is recognised as key to facilitating cultural change, as is the use of approaches which clarify values and highlight contradictions between espoused culture and culture in practice. A three-year study in which a consultant nurse post in critical care was operationalised demonstrated the achievement of an organisational culture with positive impact on the unit in which it was based, on practitioners and their practice, and also on the trust. Transformational leadership combined with other facilitative processes, expertise in the practice of nursing, and other subroles of the consultant nurse are further highlighted as influential.