This chapter provides an introduction to the concept of Evidence-based Medicine (EBM) including its history, rooted in Canada and its important role in modern medicine. The chapter both defines EBM and explains the process of conducting EBM. It includes a discussion of the hierarchy of evidence that exists with reference to common methods used to assess the levels of quality inherent in study designs. The focus of the chapter is on how to critically appraise the medical literature, as one step in the EBM process. Critical appraisal requires an understanding of the strengths and weaknesses of study design and how these in turn impact the validity and applicability of research findings. Strong critical appraisal skills are critical to evidence-based decision-making.