For people with epilepsy, knowledge of their disease is an important factor in optimizing the control of their seizures. Better-informed patients can more easily participate in the treatment process, reducing disease-related anxiety and coping better with stigma. This study was developed in a Lithuanian tertiary epilepsy center to assess knowledge of disease among people with epilepsy, to estimate differences in disease knowledge between patient groups, and to evaluate how epilepsy influences patients' daily lives. We asked patients to complete a questionnaire and collected information from outpatient cards on epilepsy etiology, type of seizures, findings of diagnostic tests, and information about patients' antiepileptic drugs. Our results showed that people with epilepsy have poor knowledge about their disease: almost half of the patients did not identify the cause of their illness or their type of seizures; most did not know the results of their EEG and neuroimaging studies. Patients also lacked general knowledge about their disease and implications for lifestyle. However, cognitive deficits were not assessed in this study, and this may have affected the answers where patients were required to recall and name their drugs or the dosage of medication. Almost half of them believed that epilepsy had changed their lives significantly and reported anxiety and constant fear of seizures. Patients were also afraid to have because of the possibility they would also have epilepsy. There is clearly a great need for improved educational intervention for people with epilepsy.