Responses of seizures to therapy is one of the most important prognostic factors in epilepsy. Absences are among the seizure types with a good response to antiepileptic drug treatment and, usually, remission before adult age. Absence patients attending an epilepsy clinic for adults can be expected to represent a group with negative bias because they have not yet remitted. Furthermore, the majority have additional generalized tonic-clonic seizures, which is a recognized negative factor in prognosis. We studied 229 adolescents and adults who were under our care for at least 2 years, and divided them into three groups according to their becoming absence free for at least 1 year: (1) responders to simple therapy (one anti-absence drug in doses not exceeding 2 g/day); (2) responders to complex therapy (one anti-absence drug in higher dose or combination of anti-absence drugs); (3) non-responders. Groups 1 and 2 can be considered jointly as responders as opposed to the non-responder group. Similarly, groups 2 and 3 can be considered jointly as a group with poor as opposed to good therapeutic response. It was found that significant differences exist between good and poor responders, and 15 factors which had a negative effect on therapeutic response could be identified. No single factor or combination was responsible for non-response, but non-responders had the highest score of negative factors. Patients with complete absence control had a 93% chance of total seizure control, and, with constant medication, relapses after 1 year of control were very infrequent. The conclusion of this study is that complete absence control is of great prognostic importance for patients having this seizure type. With active treatment using, if necessary, high doses of succinimides or valproic acid alone or in combination, excellent results can be achieved even in a patient group biased towards a poor prognosis.