OBJECTIVE: The purpose of this study is to assess the temporal course of seizure in patients with arteriovenous malformation(AVM) after radiosurgery. METHODS: This study included 48 patients with AVM who underwent LINAC radiosurgery. Seventeen patients(35%) presented with seizure before the diagnosis of AVM. Clinical symptoms, location and volume of AVM, and temporal course of seizure after radiosurgery were analyzed retrospectively. RESULTS: Among seventeen patients with seizure episode before radiosurgery, twelve(70.6%) improved progressively and one patient(5.9%) did not show change in seizure frequency during the follow up period. Transient increase of seizure frequency and subsequent improvement was observed in 4 patients(23.5%), and seizure was controlled in two of these patients during the follow-up. Cumulative seizure frequency of all patients increased transiently from six months to 18 months after radiosurgery, and then it began to decrease significantly. CONCLUSION: Radiosurgery is an effective treatment modality resulting not only in the obliteration of AVM but also improvement of epilepsy associated with AVM. However, in some patients, transient increase of seizure frequency was observed before subsequent improvement. It was around 18 months after radiosurgery that seizure frequency significantly decreased in the majority of the patients. These data suggest that there is a possibility of transient aggravation of epilepsy after radiosurgery even though epilepsy improved eventually in most of the patients.