This chapter discusses somatosensory evoked potentials (SSEPs) elicited by stimulation of large mixed nerves in the upper and lower extremities, their clinical utility, method of acquisition, and standard recording protocol. This chapter describes the major components of median and posterior tibial SSEPS, and their generator sources, emphasizing near-field and far-field contributions. How various subject related and technical factors influence these responses are discussed. Detail descriptions are provided of common SSEP abnormalities and their interpretation and correlation with dysfunction at specific levels of the somatosensory pathways. Major central and peripheral neurological disorders associated with SSEP abnormalities are also described with a detailed discussion on the abnormal patterns seen in deep coma, various demyelinating conditions, myelopathies, neuropathies, and plexopathies. A brief description of the use of SSEPs in intraoperative monitoring is provided, and more than 30 figures and 10 tables illustrate various SSEP characteristics and abnormalities. At the end of the chapter, six actual clinical cases are added and discussed under the following headings: reason for study, technical summary, SSEP findings, interpretation, and discussion.