Experimental animal models have played a crucial role not only in advancing our understanding of human atherosclerosis but also in evaluating potential therapeutic interventions as described in many parts in the previous chapters of this book. Since the first experiment using rabbits was reported by Russian researchers at the beginning of the last century, a variety of animal models have been used to study atherosclerosis. Nonetheless, genetically modified mice, especially apoE and LDL receptor KO mice, have become the most popular animal models to date. However, either in the basic research to elucidate the pathophysiological mechanisms, or in the pre-clinical bridging study to develop new diagnostics and therapeutics for hyperlipidemia and atherosclerosis, there are still many challenges that researchers must face in applying different types of experimental models: Which animal models best simulate human atherosclerosis? How do we interpret the results obtained from animal models? How do we extrapolate these findings to the clinical setting? Considering the book theme (pathology and pathogenesis of atherosclerosis), we will first provide an overview of the current status of animal models often used in atherosclerosis research and then, summarize the features of pathological features of atherosclerosis in experimental animals, and highlight the advantages and disadvantages of animal models.