OBJECTIVES: To describe key characteristics of members of the online, USA-based PatientsLikeMe® Epilepsy Community, by comparison with a widely-used USA claims database, PharMetrics®, and to assess the impact of epilepsy on patients’ lives using patient-reported data, collected through PatientsLikeMe®.  METHODS: The PatientsLikeMe® Epilepsy Community allows patients with epilepsy to record their characteristics and monitor treatment and outcomes. The system allows longitudinal entry of well-known Patient Reported Outcome instruments (e.g. QOLIE-31-P, HADS), treatments, symptoms, and seizure frequency and severity. RESULTS: By September 2010, 2613 patients had registered; 1838 (70.3%) patients with a reported diagnosis of epilepsy were analyzed. The PatientsLikeMe® Epilepsy Community tends to over-represent females compared with PharMetrics® (71.7% vs. 53.6%) and 20–50 year old patients, reflecting online user demographics. The proportions of treated patients receiving polytherapy or newer AEDs were also greater in PatientsLikeMe® versus PharMetrics® (53.4% vs. 29.2%; 82.4% vs. 66.4%, respectively). Regional coverage of PatientsLikeMe® members appeared closer to US census than PharMetrics®.  Patient-reported data from PatientsLikeMe® reflected the significant burden of epilepsy on patients’ lives. Patients experiencing ≥1 seizure during the last 4 weeks reported significantly lower quality of life (QoL) and higher levels of depression and anxiety than those not reporting seizures (all p-values <0.005). This was even more pronounced in patients reporting ≥1 generalized tonic-clonic seizure (all p-values <0.001). Driving status was clearly impacted by epilepsy; 50.6% in the PatientsLikeMe® sample did not drive (86.2% of these because of epilepsy) and 37.4% of drivers limited their driving because of epilepsy. Patients with driving limitations reported lower health-related QoL and higher levels of anxiety and depression (all p-values <0.0001). CONCLUSIONS: By sharing their records online, members of the PatientsLikeMe® Epilepsy Community provide researchers with a unique source of information. Exploring these data provides insight into the disease burden, treatment patterns and associated outcomes. UCB-sponsored