Purpose: Acute endosulfan poisoning is rare but causes significant morbidity and mortality. The aim of our study is to describe complications and features of seizure and determine factors associated with mortality in acute endosulfan poisoning. Methods: Twenty-eight adult patients with acute endosulfan poisoning admitted to our emergency department during a 15-year period were studied retrospectively. The clinical features of seizure, use of antiepileptic drugs during seizure, and hospital courses were evaluated. Clinical factors between survived group and non-survived group were compared for identification of factors associated with mortality. Results: Of the 28 patients with endosulfan poisoning, 4 patients (14.3%) died and 15 (53.6%) patients developed generalized tonic-clonic seizure. Thirteen patients (46.4%) and 5 patients (17.9%) progressed to status epilepticus (SE) and refractory status epilepticus (RSE), respectively. SE and RSE were associated with mortality. Almost all significant complications including shock, acute renal failure, hepatic toxicity, rhabdomyolysis, and cardiac injury developed in SE and RSE patients. Conclusion: SE and RSE were important contributors to death in endosulfan poisoning. Emergency physicians treating endosulfan poisoning should make an effort not to progress seizure following endosulfan poisoning to SE and RSE using a rapid and aggressive antiepileptic drug.