2.2. Sample Data of patients were included in the study if they were diagnosed with epilepsy, were followed by the epilepsy outpatient clinic, were ≥18 years of age, came to their appointments consecutively, and gave informed consent. Breastfeeding mothers, patients who were pregnant, and those whose diagnoses were in doubt were excluded. 2.3. Analysis Data from the files of the included patients were noted. The age, sex, age of first seizure, and duration of epilepsy were identified. The seizures and the epilepsy syndromes were Background/aim: This study aimed to reveal the optimum recording time of routine electroencephalogram (EEG) for adults with epilepsy. Materials and methods: In this clinical observational study we investigated features of paroxysms that emerged in EEGs recorded for 45 min in adults with epilepsy. Results: Paroxysms were detected in 38.14% of 97 patients. The probability of occurrence of paroxysm during the first 10 min was found to be statistically significantly low in comparison to the first 30 and 45 min (respectively P = 0.004, P = 0.0001). This probability was found to increase insignificantly when comparing the first 20 min with the first 30 min (P = 0.125), but it increased significantly in comparison to 45 min (P = 0.008). On the other hand, this probability was found to increase insignificantly when comparing the first 30 min with the first 45 min (P = 0.125). The cutoff point to specify the existence of interictal epileptiform discharges in the ROC analysis was found to be ≤39 min (95% CI: 0.958-1.000), and 90% of interictal epileptiform discharges were revealed during the first 30 min of EEG recording. Conclusion: The recording time of routine EEGs for adults with epilepsy should not be less 30 min.