Four children from two families with characteristics of Marinesco-Sjögren syndrome (congenital cataract, ataxia) are presented. All children had clinical and neurophysiological signs of a demyelinating polyneuropathy. Three of them developed acute rhabdomyolysis with marked weakness and CK levels of up to 40,000 U/I following a viral infection. In all children CK levels returned to normal within two weeks. Symptoms were recurrent in one of the children and resulted in a severe disability. In two other children recovery of motor function took about a month following the first attack. Metabolic disorders of the muscle were excluded by pathobiochemical examination of a muscle biopsy in one of the children. In conclusion, acute rhabdomyolysis can occur as a neuromuscular complication of Marinesco-Sjögren syndrome.