Somatosensory evoked potentials have proved to be useful for the outcome prediction of comatose patients. To date there are no reliable data with the investigation of motor evoked potentials (MEP) in this question. In the present study 60 patients with traumatic (group I) and 35 with non-traumatic coma (group II) were examined with both electrophysiological tests. It was the aim of this study to find out whether additional recording of MEP could contribute to a better prediction of the outcome than SEP alone. Our results clearly indicate that in terms of prognostic value SEP are superior to MEP. All patients with bilaterally preserved SEP and a central conduction time ≤ 6.5 msec (SEP-type la) survived whereas all patients with bilaterally absent cortical responses (SEP-type III) died. On the other hand, 12 patients (30.7 %) of group I and 11 patients (39.3 %) of group II with bilaterally preserved electromyographic responses following transcranial stimulation (MEP-type I) died. Only the bilateral absence of MEP (type III) was an unerring unfavourable prognostic sign. On the whole, we cannot recommend the use of MEP in prognostic evaluation of comatous patients.