The National Clinical Trials Registry: Cancer Trials (NCTR) was established to facilitate the identification of ongoing or unpublished clinical trials in cancer. The primary objective of the NCTR is to improve patient care by ensuring that cancer clinical trial research conducted in Australia is of a high standard, and that trial results are timely and of relevance to clinical practice. During its initial phase the NHMRC Clinical Trials Centre took advantage of its established network of cancer clinicians, who provided the NCTR with details of clinical trials in which they were currently participating. The principal investigator of each study was then contacted to obtain approval to include trial details in the NCTR. To reassure sponsors that the commercially sensitive nature of some proprietary information was appreciated, and to encourage pharmaceutical sponsors to register trials, the "in camera" registration option was introduced, which enables full or partial registration, but restricts access to details. Registration of a clinical trial is voluntary. Numerous measures have been taken to ensure the widespread promotion of the existence of the NCTR and of its aims and objectives, including presentations at meetings of professional societies. Brochures outlining the rationale for registration and instructions on how to register have been developed and circulated. Recent interest in registry activities by health care practitioners, funding bodies, government organisations, consumers and the media has been particularly encouraging. A critical appraisal checklist for clinical trial protocols has also been developed and used to assess the quality of clinical trials registered. Items on the checklist measure both objective and subjective indices of quality including an assessment of design, sample size, study outcomes, etc. Registration has been rewarded in some cases by the provision of funding for institutional data management for registered trials of a suitably high standard. Ongoing assessment will provide an alternative to peer review should the results of a trial remain unpublished after study completion. Prospective registration of clinical trials has become an accepted and useful process in the implementation of evidence-based medicine in the Australian cancer care community.