The novel anticonvulsant topiramate has been shown to have efficacy across a range of seizure types including both generalized and partial seizures in several well-designed randomized controlled trials. It has also been shown to be effective in atonic seizures associated with Lennox-Gastaut syndrome. Tolerability data show a tendency to neuropsychiatric side-effects, such as confusion and word finding difficulties, when topiramate is used in polytherapy; these side-effects are reduced in monotherapy usage. The efficacy and spectrum of seizures treated by topiramate suggests that it has an important role in managing epilepsy in people with intellectual disability. The predictable side-effects can be monitored in clinical practice and possibly reduced by slow dose increments. The data set of patients with intellectual disability is still too small to rule out idiosyncratic drug reaction.