This report describes two children who presented with status epilepticus. Both patients had hyponatremia, hypochloremia, low serum osmolality, and low urine osmolality caused by voluntary drinking of excessive quantities of water or diluted formula. Seizures were controlled by the administration of benzodiazepines, antiepileptic drugs, and hypertonic saline. Educating parents regarding hazards of excessive ingestion of fluid could reduce the incidence of this preventable and life-threatening condition.