Recent studies in animal models indicate that recombinant human erythropoietin (rhEPO) is very effective in enhancing neurological recovery after spinal cord injury (SCI). We aimed to evaluate the effect of rhEPO plus methylprednisolone sodium succinate (MPSS) compared to MPSS alone to improve neurological function of patients after SCI in a randomized clinical trial. During a 15-month period 30 patients presenting to emergency departments of two university affiliated hospitals within less than 6 hours after acute SCI were randomized to two groups. Both groups received MPSS 30 mg/kg initially and 5.4 mg/kg every hour till 23 hours if admitted within 3 hours and till 47 hours if recruited within 3-6 hours after injury. Group EPO also received 500 unit/kg rhEPO on admission and another 500 unit/kg 24 hours later instead of placebo in group MPSS. Neurologic evaluation was performed on admission, 24, 48, 72 hours and one and 6 months later. Range of patients' age was 18-65 years. There was no significant difference between patients receiving two types of treatment in neurological exam on admission (P=0.125), 24 hours after admission (P=0.108) and 48 hours after admission (P=0.085). However, one week (P=0.046), one month (P=0.021) and six months (P=0.018) after admission these differences were significant. MPSS plus rhEPO started within 6 hours after acute spinal injury may be more effective than MPSS plus placebo in improvement of neurologic dysfunction. More studies with larger sample sizes are warranted.