Individuals fulfilling diagnostic criteria for childhood absence epilepsy (CAE) and juvenile absence epilepsy (JAE) were selected from a large group of patients who were born between 1945 and 1973 and had presented with absence seizures (AS). Updated data allowed an analysis of 52 patients with CAE and of 62 patients with JAE age > or = 20 years. In CAE, complete control was achieved in 90% of patients (95%, AS only; 77%, AS + generalized tonic-clonic seizures, GTCS). Only 16% of patients with an onset < 9 years had developed GTCS. In JAE, complete control was achieved in 37% of patients (47%, AS; 37%, GTCS). These figures support the validity of the International Classification of Epilepsy (ICE). Stricter diagnostic criteria are discussed.