Anticonvulsant therapy is usually recommended before surgery in all patients affected by high grade glioma who are planned to be treated with Carmustine 1,3-bis [2 chloroetyl]-1-nitrosurea, or BCNU) wafers. In fact, phase III studies have reported a risk of seizures higher than 30% in this group of patients. The aim of the study was the evaluation of rate type time of occurrence of seizures in BCNU-treated patients in the postoperative period as well as the investigation into possible risk factors for seizure occurrence in this population. From April 2007 to September 2010, 55 patients underwent surgical removal of malignant glioma and BCNU wafers implantation at the Department of Neurosurgery of Padova. All patients were given antiepileptic prophylaxis for 3 months after surgery. Clinical data (including preoperative seizure history), radiological data, surgical treatment, antiepileptic treatment were retrospectively reviewed. Nine percent of the patients treated with BCNU wafers presented seizures in the postoperative course. Seizures were partial in 80% of cases; they occurred within 30 days after surgery and in 80% of cases within the first 7 days. Patients with preoperative seizures presented more frequently postoperative epilepsy than patients who were preoperatively seizure-free [P = 0.0006; OR = 48 (2,4;945)]. Postoperative seizures were more common among patients affected by one or more wafers related adverse event than among patients without adverse events [P = 0.006; OR = 21 (2,06;213)]; however, they did not appear associated to the number of implanted wafers. Patients with a sub-therapeutic level of AED at the seventh day after surgery presented a higher seizure occurrence [P = 0.02; OR = 11 (1,5;79,8)]. In our experience, postoperative seizures in BCNU-treated patients were less frequent than expected. Careful patient selection and postoperative monitoring could probably play a role in order to decrease seizure occurrence.