Entrapment neuropathies are common but require precise electrodiagnostic evaluation for accurate diagnosis that excludes the possibilities of other disorders. Electrodiagnostic testing in carpal tunnel syndrome, ulnar neuropathy at the elbow, and thoracic outlet syndrome is reviewed. The potential for uncommon lesions such as lipomas and ganglion cysts to cause nerve compression is also emphasized. The widening role of magnetic resonance imaging in the diagnosis of peripheral nerve disorders is discussed, and it should afford earlier diagnosis of structural lesions of nerve. Controversial entities such as radial tunnel syndrome and piriformis syndrome are discussed, as is the endoscopic surgical treatment of carpal tunnel syndrome.