The most important aspects of open access for the medical librarian are presented. Reasons for open access include access to research information, access to taxpayer-funded research, facilitation of evidence-based medicine, equity of access, promotion of author control, and controlling library costs. The two primary approaches to open access, via author self-archiving and open access publishing, are presented. Key open access policy developments are highlighted. Many of the major policy initiatives of the moment are from the research funders. From the researcher funders' point of view, open access means more research impact, more real-world impact when professionals can access the literature, and value is illustrated to the taxpayer, building support for further research funding. The world's largest medical research funders, including the U.S. National Institute of Health and the Wellcome Trust, have public access policies, and many more policies are in development. For example, two weeks ago the Federal Research Public Access Act was introduced in the U.S. Senate. One of the essential elements of open access policy is ensuring that researchers are required, not requested, to deposit works. In Canada, the Canadian Institutes of Health Research has a policy in development called Access to Products of Research; public comments are due May 15, 2006. The dramatic growth of open access - over 2,220 journals in DOAJ, over 7.3 million items in an OAIster search - is discussed, as is the idea of new roles for librarians in an open access environment.