Essential tremor (ET) is a common movement disorder in adults that interferes with the performance of functional and social activities. The goal of treatment is to minimize functional disability, reduce social handicap and improve quality of life. Although it was stated that there was no effective treatment for ET, a variety of pharmacological approaches to ET is available and new drugs for the treatment of ET are needed. We studied antitremor effect of olanzapine in 23 patients with ET. Five of 23 patients were excluded from study since they could not follow-up regularly. The completed study group were 18 patients (7 female, I I male), mean age (60.1+/-14.98), mean duration of symptoms were (21.01+/-18.90) years. 9 of 18 patients showed significant decrease in total tremor score. 7 of 18 patients reported minor side effects. In conclusion olanzapine monotherapy appears to be efficacious for treatment of ET.