Prognosis describes the trajectory and long-term outcome of a condition. Most studies indicate a better prognosis in idiopathic generalized epilepsy (IGE) in comparison with other epilepsy syndromes. Studies looking at the long-term outcome of different IGE syndromes are relatively scant. Childhood absence epilepsy appears to have a higher rate of remission compared to juvenile absence epilepsy. In absence epilepsies, development of myoclonus and generalized tonic–clonic seizures predicts lower likelihood of remission. Although most patients with juvenile myoclonic epilepsy (JME) achieve remission on antiepileptic drug therapy, <20% appear to remain in remission without treatment. Data on the prognosis of other IGE syndromes are scarce. There are contradictory findings reported on the value of electroencephalography as a predictor of prognosis. Comparisons are made difficult by study heterogeneity, particularly in methodology and diagnostic criteria.