Background: Investigation of the expression of platelet-derived growth factor (PDGF)-beta and glial fibrillary acidic protein (GFAP) in rats with spinal cord injury as a marker of neurologic recovery between groups treated with erythropoietin (EPO) and methylprednisolone (MP). Methods: Thirty adult female rats were randomly divided into three even groups. A laminectomy was applied to thoracic ninth vertebra and contusion injury was induced by extradural application of an aneurysm clip. Group 1 rats received one-time intrathecal administration of normal saline, group 2 rats received MP, and group 3 rats received EPO. Motor neurological function was evaluated by the Basso, Beattie, and Bresnahan (BBB) locomotor rating scale. Thirty days after the surgery, T8-10 segments of the spinal cords were extracted and the immunohistochemical assay revealed the number of PDGF-beta- and GFAP-positive cells. Results: Evaluation of the last control animal showed that BBB score in the EPO group showed an increase from 1 to 12 (p < 0.05). The immunohistochemical assay revealed that the number of PDGF-beta- and GFAP-positive cells was significantly higher in EPO group (p = 0.000) when compared to MP and control groups. After studying the effect of PDGF-beta expression on the locomotor function, we determined that PDGF-beta expression and locomotor function after a spinal injury has a strong relationship (p < 0.05). Conclusion: EPO seems to better increase the expression of PDGF-beta, thus produce better results in locomotor functions when compared to MP.