Clobazam must be considered as an add-on therapy for patients with epilepsy. The aim is to evaluate the effectiveness and safety of CLOBAZAM as add-on therapy in patients whose seizures are not adequately controlled with the monotherapy through a prospective observational study. A perspective, observational study, with assessment in 3, 6, 9 and 12 months through personal interviews and seizure diaries helped assess seizure control and adverse events. Results that led to the conclusion that CLOBAZAM is an effective and well-tolerated as add-on therapy after the failure of previous monotherapy.