BACKGROUND Buspirone, a 5HT-agonist and D2-dopamine antagonist/agonist, has modest beneficial effects in younger individuals with cerebellar ataxia. However, it is unclear whether it is beneficial and tolerable in older ataxic individuals. OBJECTIVE To determine if an older individual with cerebellar ataxia would benefit from and tolerate buspirone. METHODS We performed a single-subject, double-blinded, placebo-controlled randomized-phase study. The 80 year-old subject was to undergo six 4-week testing periods, divided randomly into three treatment and three placebo arms with a 2-week washout period between each arm. Treatment consisted of buspirone hydrochloride. Outcomes were clinical gait and balance testing, posturography testing, and subjective measurement of balance confidence. RESULTS There were no statistically significant objective improvements with buspirone. The subject experienced a subjective improvement in balance confidence and tolerated treatment. CONCLUSIONS Single-subject studies can help when it is unclear whether drug trial results with young subjects are generalizable to an older subject. This single-subject study determined that buspirone was tolerable but not clearly beneficial for an ataxic older individual.