In adults, botulinum toxin type A has been studied as a potentially effective treatment for chronic daily headache. For pediatric chronic daily headache, the literature evaluating efficacy of botulinum toxin type A is sparse, with no studies assessing tolerability. The purpose of this retrospective case series study was to assess tolerability and efficacy of botulinum toxin type A in the treatment of pediatric chronic daily headache. The series comprises 10 patients (ages 11-17 years) who received a standard 100-unit dose of onabotulinumtoxinA (trade name, Botox) for refractory chronic daily headache. Attention was given to therapeutic history, efficacy, and tolerability. The patients had attempted an average of 8.0 ± 2.40 S.D. therapies prior to botulinum toxin type A. Most patients reported adverse events from at least one of these prior medications. With botulinum toxin type A, four patients (40%) reported subjective but clinically meaningful relief, consisting of a decrease in headache intensity, and two patients additionally noted a decrease in headache frequency. The four responders noted improvements in quality of life. Three patients experienced minor adverse events from botulinum toxin type A. This case series suggests that botulinum toxin type A can be well tolerated and may be a useful therapeutic in pediatric patients with highly medically intractable chronic daily headache.