Presently, there are few electrodiagnostic medicine techniques to evaluate lesions affecting the thoracic nerve roots or spinal cord. A new electrophysiologic technique to assess these structures, intercostal somatosensory-evoked potentials (SEPs), is described. Thirty neurologically normal subjects were used in this investigation to generate intercostal SEPs. Bilateral intercostal SEPs were easily elicited after stimulation of the third intercostal nerves just lateral to the sternum anteriorly. Intercostal SEPs were also easily elicited from the fifth, seventh and ninth intercostal nerves along the anterior axillary line bilaterally. Intercostal SEPs are not only easily and painlessly obtained, but are specific for individual spinal levels. This SEP method will provide the clinician with another neural stimulation procedure to assist in the diagnosis of both central and peripheral thoracic neural compromise.