Intrathecal baclofen (ITB) is an effective treatment for both spasticity and dystonia in people with cerebral palsy (CP). Its use is becoming increasingly common. ITB is typically associated with fewer side effects than the oral form of the product, but there are risks related to the hardware needed for intrathecal delivery. Much of what has been reported in the literature about ITB is based on experience with children or groups of children and adults; few reports exclusively address its use in adults with CP. These reports indicate that muscle tone is consistently reduced, but there is some variability in functional outcomes. Few well-controlled studies have been done. Controversies remain concerning ITB, including whether a trial is needed before pump implantation, proper catheter tip placement, and programming options, as well as whether it contributes to the development or progression of scoliosis. These and other unanswered questions should be addressed in a systematic way.