Aim:Electrophysiological evaluation of the outcomes of spinal procedures is important for neurosurgeons. Somotosensorial evoqued potentials (SSEPs) are used for electrophysiological evaluation of tethered cord syndrome (TCS) and spinal intradural tumors (SIT). The aim of this study is to document the electrophysiological outcomes of surgery for TCS and SIT and to compare the results based on the preoperative diagnosis. Material and Methods: The data of 30 patients, who were operated for TCS and SIT between 2011 and 2013, were reviewed retrospectively. Surgical release of the spinal cord was performed for TCS and tumor removal was performed for SIT. Median and tibial nerve SSEPs at the left and right sides were measured at preoperative, early and late postoperative periods and compared statistically based on the diagnosis and the time of electrophysiological assessment. Results:The diagnosis was TCS in 12 (40%) patients and SIT in 18 (60%) patients. There was a significant difference between preoperative, and early and late postoperative SSEPs values. Tibial nerve latencies were prolonged in the early postoperative, but shortened in the late postoperative period. Contrary, median nerve latencies were shortened in the early postoperative, but prolonged in the late postoperative period. There was no significant difference between the TCS and SIT groups based on the surgical intervention.Conclusion:Tibial nerve latency may be prolonged in early postoperative period of TCS and SIT patients. But electrophysiological changes were not predictive for these patients. Further studies with more patients are needed for other spinal lesions.