Objective To investigate the reliability,superiority and value of combined monitoring of motor evoked potentials(MEP) and somatosensory evoked potentials(SEP) during intramedullary spinal cord tumor surgery under total intravenous anesthesia.Method 72 patients with intramedullary spinal cord tumor were monitored somatosensory evoked potentials and muscle motor evoked potentials during operation.McCormick scale was adopted to evaluate the patients' clinical nerve function.The postoperative to preoperative McCormick grade variation and combimed monitoring of SEP and MEP were compared in this group.Result 14 patients' nerve function was improved.The findings of monitoring were evaluated in 18 patients with depressed McCormick scores.There was significant difference in the latency and amplitude of waves between pretreatment and post-treatment (P<0.05).The changes of SEP and MEP were correlative with the changes of spinal cord function.Conclusion Combined monitoring of SEP and MEP could help to improve postoperative McCormick scale outcome significantly for patients with intramedullary spinal cord tumor.The waveform of either SEP or MEP might be stable and reliabie in monitoring patients under total intravenous anesthesia.It might be helpful in avoiding 'false negative and/or false positive results'as well as the postoperative neurological sequelae. Key words: Spinal cord; Somatosensory evoked potentials; Motor evoked potentials