A case of infantile neuropathy with signs of respiratory distress and impaired abdominal movements from the neonatal period was reported. Muscle biopsy revealed type II fiber predominance and atrophy, and the sural nerve biopsy demonstrated the absence of myelin in almost all of the axons. Onion bulb formation or myelin debris was not observed. The features of myelin deficit without active myelin breakdown and onion bulb formation, and the finding of muscle pathology, indicating the absence of spinal muscular atrophy, suggested that the case under study was identical to that of hypomyelination neuropathy. Peripheral neuropathy characterized by the excessive reduction or absence of myelination is a rare condition and only about 10 such cases have been reported in the literature (Lyon 1969, Joosten et al 1974, Karch et al 1975, Kasman et al 1976, Kennedy et al 1977, Moss et al 1979, Towfighi 1981). A case of infantile neuropathy with defective myelination and respiratory distress originating in the neonatal period was reported.