Abstract The clinical characteristics of 12 cases of postictal psychosis treated at Taipei City Psychiatric Center, Taipei, Taiwan, were retrospectively reviewed. Increased seizure frequency, especially with generalized tonic–clonic seizures, was the major risk factor predisposing to postictal psychosis. The psychotic symptoms were variable with delusions and/or hallucinations. These patients showed a much longer history of epilepsy (21.9 ± 10.7 years) prior to the development of postictal psychosis than has been previously reported. The possible mechanisms in the pathophysiology of psychosis in epileptics were discussed.