Despite the aligned aspirations of many applied scientists and policy-makers that science should contribute directly to policy decisions, there are significant gaps between what scientists provide and what policy-makers can use. This article outlines the features that encourage effective adoption of scientific advice in public policy. It reviews some of the major impediments to its use. It describes governance mechanisms that aim to overcome these impediments, and discusses their strengths and weaknesses. Opportunities exist for designing governance mechanisms that will better support the development and persistence of the personal relationships that underpin the most effective delivery of science for policy.