Revered in some cultures but persecuted by most others, epilepsy patients have, throughout history, been linked with the divine, demonic, and supernatural. Clinical observations during the past 150 years support an association between religious experiences during (ictal), after (postictal), and in between (interictal) seizures. In addition, epileptic seizures may increase, alter, or decrease religious experience especially in a small group of patients with temporal lobe epilepsy (TLE). Literature surveys have revealed that between .4% and 3.1% of partial epilepsy patients had ictal religious experiences; higher frequencies are found in systematic questionnaires versus spontaneous patient reports. Religious premonitory symptoms or auras were reported by 3.9% of epilepsy patients. Among patients with ictal religious experiences, there is a predominance of patients with right TLE. Postictal and interictal religious experiences occur most often in TLE patients with bilateral seizure foci. Postictal religious experiences occurred in 1.3% of all epilepsy patients and 2.2% of TLE patients. Many of the epilepsy-related religious conversion experiences occurred postictally. Interictal religiosity is more controversial with less consensus among studies. Patients with postictal psychosis may also experience interictal hyper-religiosity, supporting a "pathological" increase in interictal religiosity in some patients. Although psychologic and social factors such as stigma may contribute to religious experiences with epilepsy, a neurologic mechanism most likely plays a large role. The limbic system is also often suggested as the critical site of religious experience due to the association with temporal lobe epilepsy and the emotional nature of the experiences. Neocortical areas also may be involved, suggested by the presence of visual and auditory hallucinations, complex ideation during many religious experiences, and the large expanse of temporal neocortex. In contrast to the role of the temporal lobe in evoking religious experiences, alterations in frontal functions may contribute to increased religious interests as a personality trait. The two main forms of religious experience, the ongoing belief pattern and set of convictions (the religion of the everyday man) versus the ecstatic religious experience, may be predominantly localized to the frontal and temporal regions, respectively, of the right hemisphere.