Six cases of congenital myotonic dystrophy are described. Only two survived the neonatal period. There were seven neonatal deaths in the immediate families and six reported miscarriages. Of the two survivors one is moderately retarded and the other at 9 months is at the developmental level of 5-6 months. Facial diplegia and depressed deep tendon reflexes are clues to the presence of neonatal myotonic dystrophy and the diagnosis is confirmed by examining the mother who will show some of the features of the disorder. Infants may also present with non-specific respiratory problems, hypotonia and poor sucking.