EMG and nerve conduction studies have limitations and require particular consideration in children. The indications and the main results are considered from the study of 1624 EMGs in 1385 children under 15 years old seen over a period of 3 years. Classification of cases was based on clinical criteria. The diagnostic yield of EMG is emphasized in the evaluation of 122 children with hypotonia and weakness (all under 3 years old); abnormalities were demonstrated in 48% leading to the diagnosis of spinal muscular atrophy in 16%, of congenital myopathies in 11%, and of peripheral neuropathies in 8%. In 103 children with hypotonia associated with mental deficiency and/or seizures, evidence of a peripheral neuropathy was shown in 20%. EMG abnormalities allowing the diagnosis of hereditary motor and sensory neuropathies or myopathies were demonstrated in a wide range of clinical conditions. EMG appears to be useful for the early detection of hereditary myopathies or neuropathies in asymptomatic children. It may have also a prognostic value as in adults, especially in nerve traumas.