Electrodiagnostic examination is used relatively little for the assessment of central nervous system disorders. Nevertheless, it should provide useful information for the neurologists in their clinical evaluation of the patient. It could partly contribute to the correct diagnosis of the illness, its differential diagnosis with respect to diseases with smilar clinical presentation and, most of it all, to the identification of the pathophysiological abnormalities possibly responsible for the symptoms and signs characterizing the disease. Electrodiagnostic examination in Neurology enables us to design specific and customized methods for functional examination of mechanisms and circuits of the central nervous system, destined to enhance our understanding of pathophysiological mechanisms. This objective will be more readily accomplished from a common base of understanding and support between clinicians and electrodiagnostic specialists in which scientific curiosity and technical skills can complement each other effectively. In this article, we review some of the most relevant neurophysiological findings in patients with parkinsonian syndrome, with special focus on those that may contribute to the differential diagnosis between parkinsonisms.