Infantile spasms and the Lennox-Gastaut syndrome are considered to be age-specific pediatric epileptic syndromes and together constitute a significant percentage of medically resistant seizures in childhood. Twenty children, ages 4 to 28 months (median, 12 months), with medically refractory infantile spasms or the Lennox-Gastaut syndrome, were treated with the investigational benzodiazepine nitrazepam in an open-label study. Daily dosage of nitrazepam ranged from 0.5 to 3.5 mg/kg, with a median dosage of 1.5 mg/kg, divided into two doses per day. Side effects included pooling of oral secretions (12 children) and sedation (six children); however, no serious side effects were seen. Responses to nitrazepam were as follows: five complete responses (cessation of all seizures), seven partial responses (greater than 50% reduction of seizures), and eight with no response. Median duration of response was 9 months: (range, 4 to 16 months) in children with infantile spasms and 13 months (range, 8 to 26 months) in children with the Lennox-Gastaut syndrome. Nitrazepam is an effective anticonvulsant in this small cohort of children with medically refractory infantile spasms and the Lennox-Gastaut syndrome, resulting in a 25% response rate and only modest side effects.