Topiramate is a novel anticonvulsant agent with a broad spectrum mechanism of action, and recent clinical reports indicate that it may have mood stabilizing properties in bipolar disorder. Therefore, we treated a 41-year-old woman who had 12 previous hospitalizations for acute mania during a 10-year history of bipolar I disorder with this compound. Since 1991, the patient had been treated with carbamazepine, valproate and lamotrigine with limited success. At the beginning of a new manic episode, topiramate was started in the outpatient clinic. Eight weeks after initiation of treatment, the patient was hospitalized. This inpatient treatment lasted less than 3 weeks. Subsequently, the patient has not been hospitalized again. Topiramate was well tolerated. Even though, during subsequent topiramate treatment, a serious life event (suicide attempt of brother) induced re-occurence of the patient's psychopathology, which did not require hospitalization. Fortunately, inpatient treatment was not necessary due to an increase of topiramate dosage and addition of risperidone and clonazepam. The patient, now on 200 mg/day, is mostly asymptomatic and has functioned well for over 17 months, in contrast to 13 hospitalizations during the previous 10 years.