Purpose: In highly doses, endosulfan lowers the seizure threshold and elicits central nervous system stimulation, which can result in seizures, respiratory failure, and death. Management of seizure control is essential for survival and prognosis of intoxicated patients. This study assessed whether seizure time was an independent predictor mortality in patients with endosulfan poisoning. Methods: This retrospective study enrolled patients with endosulfan poisoning presenting to Masan Samsung Hospital and Gyeongsang National University Hospital from January 2003 to December 2008. The data were collected from clinical records and laboratory files. Using a multivariate logistic analysis, data on the total population was retrospectively analyzed for association with mortality. Results: Of the 24 patients with endosulfan poisoning, nineteen (79.1%) experienced seizure. The patients in the seizure group showed significantly lower Glasgow coma scale score, base excess, bicarbonate, and significant existence of mechanical ventilation, as compared to the non seizure group (n=5). Seizure, Glasgow coma scale score, systolic blood pressure, bicarbonate level, need for respiratory support, pulse rate, respiratory rate, pH, base excess, and seizure time were associated with mortality. The fatality rate of endosulfan poisoning was 54.1% with higher mortality among patients experiencing. Longer seizure time was associated with higher mortality. Conclusion: Seizure time can be a significant independent predictor of mortality in patients with acute endosulfan poisoning. Physicians should aggressively treat for seizure control in patients with acute endosulfan poisoning.