We report our experience with 300 consecutive parenteral doses of lorazepam (LOR) for status epilepticus (SE) or serial seizures in 77 children and young adults. The median dose for SE in children less than 12 years old was 0.10 mg/kg. LOR stopped the SE in 79% and diminished the intensity of SE in an additional 4%. Prior acute or chronic anticonvulsant use (excepting chronic benzodiazepines) did not alter effectiveness or increase side effects. Duration of freedom from seizures following acute therapy was independent of LOR dosage. In patients requiring sequential doses, LOR becomes progressively less effective. Side effects were few and, when present, always associated with a single or first dose in a series. LOR is a safe and effective acute anticonvulsant agent for in-hospital control of SE in the pediatric age group. Tachyphylaxis of anticonvulsant action occurs when serial doses are used.