The paper presents the clinical features and laboratory data of a 6-year-old boy with centronuclear myopathy. No familial susceptibility was disclosed. The clinical signs are displayed with a congenital foot deformity and with the child's beginning to walk further symptoms and signs appeared. They simulated the picture of the limb-girdle type of muscular dystrophy. EMG findings showed myopathic type of motor unit disintegration at the muscle level. The morphological examination disclosed the characteristic features of the disease: central sarcolemmal nuclear and perinuclear loss of myofibrils. These changes affected both types of muscle fibers.