This paper gives an account of the process of refining the content validity of an audit tool, which defines and measures best practice in colorectal cancer nursing and identifies areas for development. The European Oncology Nursing Society (EONS) and AstraZeneca collaborated to develop the Nursing in Colorectal Cancer Initiative (NICCI). The initiative was funded through educational grants from AstraZeneca and led by EONS. It is a project with two components, education and audit. The education component culminated in a manual that provides a core set of materials concerning fundamental aspects of colorectal cancer, to foster a common understanding amongst nurses at national and international levels. An audit tool was developed to measure standards of nursing care in relation to the delivery of cytotoxic chemotherapy to patients with advanced colorectal cancer. The content validity of the audit tool was established in three stages by expert panel review with revisions made to the content and organisation of the audit measures at each stage. The standards set by the NICCI Audit Project have key implications for multi-professional practice in colorectal cancer care.