In the spring of 2008, the U.S. National Institutes of Health revised its public access policy from a voluntary process to a mandate, requiring that the author's final manuscripts of peer reviewed papers reporting work done with NIH funding be deposited into PubMed Central and made freely available to the public no more than 12 months after the formal publication of the paper. The implementation of the mandatory policy has presented challenges and opportunities for those institutions with a high proportion of NIH-funded research. Librarians in those institutions have taken on a variety of activities in support of the implementation of the policy. This session will present an overview of the policy and its implementation, and discuss some of the current and potential roles for librarians, as well as possible impacts on the role of the library going forward.