BACKGROUND: Somatosensory evoked potentials (SSEPs) have been frequently used to monitor cerebral ischemia during cerebral aneurysm surgery. The relation of SSEP changes and postoperative neurologic deficits due to ischemia have been studied many times but the relation according to the location of temporary clips have not yet been evaluated. METHODS: We studied 81 patients undergoing cerebral aneurysm surgery. Median nerve SSEP was used for temporary clipping of internal carotid artery (ICA) or middle cerebral artery (MCA) and posterior tibial nerve SSEP for temporary clipping of anterior cerebral artery (ACA). SSEPs were recorded after induction of anesthesia and dural opening (control value), during temporary clipping, and after relieving temporary clips. A change in cortical amplitude of more than 50%, as compared with control was considered as `significant'. The presence of significant SSEP changes and neurologic deficits according to the location of temporary clips were analyzed using 2 test. RESULTS: Significant changes in M-SSEP were recognized in 7 of 31 patients of MCA clipping. 2 patients showed neurologic deficits in these 7 patients. Significant changes in M-SSEP were recognized in 7 of 26 patients of ICA clipping, but there was no neurologic deficit. Significant changes in P-SSEP were recognized in 4 of 24 patients of both ACAs clipping. Only 1 patient showed neurologic deficit, but SSEP change of this patient was insignificant. Temporary clip time was significantly prolonged if there were neurologic deficits. CONCLUSION: SSEPs may be able to be used to detect significant cerebral ischemia due to temporary clipping. Especially, M-SSEP was useful to detect cerebral ischemia due to MCA temporary clipping.