Abstract. Pigs are increasingly being recognized as good large-animal models for translational research, linking basic science to clinical applications in order to establish novel therapeutics. This article reviews the current status and future prospects of genetically modified and cloned pigs in translational studies. It also highlights pigs specially designed as disease models, for xenotransplantation or to carry cell marker genes. Finally, use of porcine somatic stem and progenitor cells in preclinical studies of cell transplantation therapy is also discussed. Key words: Cloned pig, Gene knockout, Transgenic pig, Translational research (J. Reprod. Dev. 55: [225][226][227][228][229][230] 2009) t present, pigs are not only considered important livestock but are also essential large-animal models in various types of biomedical research [1][2][3][4][5][6]. Furthermore, due to recent technological advances in genetic modification and somatic cell cloning, the range of applications for porcine models has increased markedly [7][8][9][10][11][12][13][14]. The present review focuses on development of genetically modified and cloned pigs and their use in translational studies.Translational research plays an important role as a bridge between basic science outcomes and the clinical realm, leading to development of novel therapeutics. However, disparate findings for rodent models and humans have hindered the translation of rodent data into actionable technologies for patients [15]. In contrast, pigs have many anatomical and physiological similarities to humans, including their cardiovascular systems, omnivorous gastrointestinal tracts and central nervous systems. Their physical sizes are also more comparable to that of humans, rendering pigs more appropriate for development of new surgical or endoscopic techniques.In the future, more advanced translational research may be conducted by improving the clinical relevance of pig models through genetic engineering. This article reviews the current status and future prospects of genetically modified pigs in preclinical studies of stem and progenitor cell therapy, the development of disease models and xenotransplantation.