We studied four patients affected by progressive myoclonic epilepsy: three patients had the clinical features of Lafora's disease while the fourth was affected by a Lundborg's type of myoclonic epilepsy. In all above cases we found no specific electroencephalographic records of Lafora's disease; muscle histochemistry was useful for the diagnosis and the demonstration of PAS positive and NADH-TR positive Lafora's bodies. The Authors discuss the nosographic situation of Lafora's body disease among the progressive myoclonic epilepsies.