The complexity of healthcare buildings continues to increase, influenced by developments in technology, rising expectations for high quality care expressed by the ageing population in many first world countries, and the diversification of care models away from the traditional hospital to various care settings in the community, including the patient’s home. The challenge is to accommodate this complexity in the design of appropriate physical spaces that support clinicians in the delivery of high quality care that is safe and ensures good clinical outcomes by promoting good patterns of clinical teamwork and communication. At the same time such space must also balance the need to promote and safeguard the needs of the patient in terms of providing environments that assist rather than hinder healing, with the interests of those funding and managing care delivery such as health service organizations or government bureaucracies whose focus is often on the ‘bottom line.’ Finally, we need to deliver architecture that will enhance the human spirit and promote well-being for those occupying the facilities we design. This paper examines the interaction of stakeholders and ‘evidence’ in the decision-making processes that necessarily accompany the development of evidence-based health facility guidelines for use for the design of hospital projects in Australia and New Zealand, both developed nations in the Asian-Pacific zone. Developed as a briefing tool for all public projects these ‘free’ web-based guidelines are also used widely in the private sector to ensure that a commonly acceptable minimum standard of design is achieved consistently across the Australasian region. This paper will look at the processes that develop these guidelines, including their reliance on ‘evidence’ from research including traditional academically derived research findings and also methods of research and evaluation that are more practice-based. These include post occupancy evaluation of selected projects as a tool for informing review and update of current guideline provisions and examination of how findings from such studies become the ‘evidence’ that underpins future guideline development.