In the last years, stem cells have drawn the attention of various sectors of society for many reasons. From the basic point of view, stem cells represent an ideal model to study cell differentiation and self-renewal mechanisms. However, their potential in cell therapy and regenerative medicine has triggered the increasing amount of knowledge in this area. Mesenchymal stem cells belong to the select group of adult stem cells. They have differentiation potential towards mesenchymal tissues such as bone, cartilage, stroma and fat. Recently, both in vivo and in vitro reports have shown a greater plasticity of mesenchymal stem cells, showing not only a mesenchymal cell fate but also those leading to endothelial, nervous and muscular lineages. For these reasons, the study of mesenchymal stem cells has gained great interest and many articles have been published. In the present review, we have presented a global vision of this topic, including its history, biologic features, sources, isolation methods and an overview on their clinical application.