Objective: The clinical usefulness of the cauda equina motor conduction time (CE-MCT) is well established either by magneticor electrical stimulation of the lumbar roots at the lumbar spine levels. However, the cauda equina sensory conduction time (CE- SCT) is not studied systematically in human adults.Methods: Lumbar laminar electrical stimulation from the level of theL1 and L5 vertebrae was applied using needle electrodes.The smallest M-responses obtained from both soleus muscles were considered as the motor threshold for the L1and L5 motor root levels. Afterwards, with the needles in the same place, the connection cables were removed from the stimulation channel and replaced to the recording channel, then the sensory program of the electromyograph was selected. The posterior tibial nevre was excited with superficia lbipolar electrodes from the popliteal fossa, and after a very slight muscle twitch was observed the intensity was reduced slightly. Therefore, the pure sensory fibers were stimulated. Cauda equina sensory action potentials were recorded and averaged at the laminar levels of L1 and L5 in the spine. Twenty adult normal controls were studied. Results: The monopolar recordings of cauda equina sensory responses at the L1 and L5 laminar levels were measured from their first positive peaks and the CE-SCT was found as 1.9±0.4 msec (mean ± SD) and ranged from 1.0 to 2.8 msec. Conclusion: The method of CE-SCT recording and calculation is very easy to use and applicable in all normal adult subjects. Themean CE-SCT value is similar to those found for CE-MTC.