Seizure is a temporary symptom or sign which is caused by an abnormal electrical stimulation of brain. Depending on whether a seizure has preceding factors or not, it can be further categorized into provoked and unprovoked seizure. In provoked seizure, it is important to find a cause for treatment. In this study, we would like to report a case of a 6 year-old male child with seizure caused by organophosphate poisoning. The patient's chief complaint was his decreased mental status accompanying seizure. Initially, status epilepticus was suspected but the response to anticonvulsants was not good, and resulted in prolonged respiratory failure. After 3 hours, the patient showed signs of cholinergic crisis. In response, atropine was administered and the condition improved. If respiratory failure or mental confusion persists even after cessation of seizure in status epilepticus, repetitive physical and neurological examinations should be carried out to find preceding factors. Even though the recent incidence of organophosphate poisoning has decreased, we would like to emphasize from our study that it should be considered as a preceding factor for seizure.