Juvenile myoclonic epilepsy (JME) is a special syndrome within the primary generalized epilepsies which is characterized clinically by irregular jerks of shoulders and arms (so-called impulsive petit mal) after awakening and electroencephalographically by bilateral-synchronous 4-6/s spike-wave complexes, often in the form of multispike-waves. The age of onset for this syndrome which occurs in 4-6% of all epilepsies is predominantly between 12 and 18 years. It mostly starts with isolated jerks which as a rule are soon followed by generalized tonic-clonic seizures (TCS). Jerks and TCS are provoked by sleep deprivation and predominantly occur after awakening (awakening epilepsy). Sleep deprivation and photostimulation are also very efficient in provoking specific EEG patterns. Exogenous factors have no etiological significance. Genetic studies suggest a polygenetic mode of inheritance and a lower threshold of manifestation in women. JME can be controlled very well by valproate and/or primidone. A complete cure, nevertheless, does not seem to be possible. Within the group of primary generalized epilepsies beginning in adolescence JME is closely related nosologically to the syndrome of juvenile absences and the syndrome of pure grand mal on awakening.