Electrodiagnostic studies are physiologic studies of the lower motor and sensory neuron unit (nerve roots, plexus, peripheral nerves, and muscles) to determine if there are any problems along this “pathway.” They define the type of problem, its precise location, its extent, and its acuity or chronicity. These studies serve as a diagnostic tool and, as such, should be used when results will help guide intervention or therapy. They may also be used when prognostic information regarding lesions to the peripheral nervous system is needed. Basic studies consist of 2 separate but equally important parts: electromyography (EMG) and nerve conduction studies (NCS). EMG involves needles but no electrical stimulation; the opposite is true for NCS. Uses of electrodiagnostic studies in the evaluation of painful syndromes commonly encountered in the ambulatory care setting will be presented, including specific practical examples such as carpal tunnel syndrome, peripheral neuropathies, and radiculopathies. Pitfalls and contraindications will be presented with emphasis on which patients should and should not be referred due to these studies’ virtues and limitations.