This article is part of a series written for people responsible for making decisions about health policies and programmes and for those who support these decision makers. In this article, we discuss the following three questions: What is evidence? What is the role of research evidence in informing health policy decisions? What is evidence-informed policymaking? Evidence-informed health policymaking is an approach to policy decisions that aims to ensure that decision making is well-informed by the best available research evidence. It is characterised by the systematic and transparent access to, and appraisal of, evidence as an input into the policymaking process.