Recognition of the significance of juvenile myoclonic epilepsy (JME) in the English-language neurological literature is relatively new. There are many factors responsible for delay in diagnosis of JME, including lack of familiarity with the syndrome, failure to elicit a history of myoclonic jerking and absence or generalized tonic-clonic seizures predating myoclonic jerks in some patients.The medical and electroencephalographic (EEG) records of seven Chinese children with JME, four males and three females, were reviewed.The age of onset ranged from 10 to 14 years with mean 11.8 +/- 1.6 years. The precipitating factors were sleep deprivation (5/7), photostimulation (3/7), hyperventilation (2/7) and menstruation (1/3). Childhood and juvenile absence epilepsies predated JME in three and one patients, respectively. All patients had concomitant grand mal on awakening. Generalized 3-4 Hz polyspikes-wave complexes occurred in all patients, and two patients had additional 3-4 Hz spike-wave complexes. These activities were provoked with photic stimulation (3/7) and hyperventilation (2/7). All patients were treated with valproate for more than four years, and relapse occurred six months to one year after discontinuation of valproate.JME is a benign generalized epilepsy with a strong genetic basis. Valproate is the drug of choice up to now, but long-term (life-long) medication may be needed.