Among the entrapment neuropathies, ulnar neuropathy at the elbow is second only to carpal tunnel syndrome in frequency; however, diagnosis and management are considerably more difficult in ulnar lesions than in carpal tunnel syndrome. Electrodiagnosis is the most important means of identifying and localizing ulnar neuropathies at the elbow, but even sophisticated techniques may sometimes fail to confirm diagnosis and localization preoperatively. Mild lesions are best managed conservatively. More severe lesions require surgical intervention. Simple decompression is now preferred over transposition in the majority of cases, but careful correlation of electrodiagnostic abnormalities and findings at surgery are necessary to ensure optimal outcome.