Main outcome: The safety and effect of mesenchymal stem cell therapy on spinal cord injured patients will be assessed. Design: 30 patients with spinal cord injury will be selected and will be divided randomly into two groups. Around 10 million cells (three times) will be injected; MRI and physical assessments before and after cell therapy will be done by a physician who does not know the groups. Setting and conduct: Cells will be isolated from bone marrow of patient under aseptic conditions; cells will be culture in DMEM high glucose until proliferation and the mesenchymal stem cell type will be identified by immunostaining. After collection of enough mesenchymal stem cells they will be injected in to the patient's subarachnoid space. Participants, including major eligibility criteria: Patients must have 13-60 years old, patients must not have fever, convulsion and meningitis and any other infectious disease, the health condition of the patients must be stable, patients must have self control on breath, by occurrence of any side effect such as fever, convulsion or tumor that patient will be excluded from study. Interventions: Patients will have one bone marrow puncture and three subarachnoid injections of stem cells (10million/each). Variables: Main variables are: improvement in sense and motor function, MRI of injury size and type, physical examinations results, effect of each injection on improvement , effect of age on improvement, control on urination and defecation, tumor formation, fever and convulsion and any other complication or side effect occurrence will be assessed.