Electromiography (EMG) plays a key role in the evaluation of patients with neuromuscular diseases. It can be considered an extension of the neurological examination. So it must be individualized and based on differential diagnosis. We have analized data about EMG performed in a period of four months in the Unit of Neurophysiopatology of University of Bari and Foggia. Data collected show that in this period we have received 807 EMG bookings: we have performed 604 exams (75%) of whom 405 exams had pertinence with differential diagnosis (50%), 199 (25%) had no pertinence; 203 patients (25%) did not turn up for the exam. At Neurophysiopathology of Foggia we have received 540 EMG booking: we have performed 504 neurophysiological studies. In the total amount of EMG performed 326 had pertinence (60%), 178 had no pertinence (33%) and 36 patients did not turn up for the exam (7%). Data collected show that physicians, medical practictioners, neurologists and other specialists share similar difficulties to make a correct differential diagnosis in the field of neuromuscular diseases and that EMG can be the most useful test in clarifying the diagnosis only after a correct clinical examination.