This randomized double blind, placebo-controlled crossover study investigated the antidyskinetic effects of levetiracetam in Parkinson s disease. METHODS: Sixteen participants with levodopa-induced dyskinesia were enrolled. Hourly videotaped dyskinesia assessments scored by the Goetz method and hourly Unified Parkinson s Disease Rating Scale motor subscale scoring were conducted on 1 day at the end of each treatment period. RESULTS: Dyskinesia was slightly less on placebo (P = .26). Patient diary records also showed less dyskinesia on placebo (P = .10). Parkinsonism was a little worse on levetiracetam, at borderline statistical significance (P = .05). CONCLUSIONS: Levetiracetam was well tolerated at doses up to 2000 mg per day, but we did not detect any antidyskinetic properties.