In this book, based on our own experience, we describe the preclinical bases of cell transplantation in injured spinal cord and the clinical results that today can be obtained using autologous bone marrow mesenchymal stromal cells (MSCs). In 2004 we demonstrated for the first time benefit of local transplantation of MSCs in rodents with complete and chronically established spinal cord injury (SCI). The difficulty of maintaining long-term animals with complete SCI and the need to confirm in upper mammals the findings obtained in rodents has taken more than 10 years of preclinical research before applying these new techniques to humans with perspectives of biosafety and efficacy. Although we are not yet able to cure a paraplegic patient, cell therapy with autologous MSCs is currently configured as the best option and offers new hope to patients suffering from spinal cord injury (SCI), improving their quality of life. In the coming years, the refinement of these techniques, a betterknowledge about its mechanism of action, and an adequate selection of patients will change the concept of the irreversibility of traumatic paraplegia.