Fifty-three patients with parkinsonism, either with intractable symptoms despite optimum-dosage levodopa therapy or with adverse effects from levodopa limiting its usefulness, were treated with bromocriptine, with gradually increasing doses until benefit or adverse effect was encountered. All were initially maintained on optimal levodopa therapy. Improvement was seen in 26 patients, of whom 19 (36 percent of the total 53 patients) had sustained improvement. Effective doses of bromocriptine ranged from 5 to 90 mg per day. Improvement occurred in all categories of clinical problems, including patients who lost some benefit from chronic levodopa therapy as well as those with adverse effects from levodopa. A high incidence (70 percent) of adverse effects of bromocriptine limited the usefulness of this drug. Since one cannot predict which patients might benefit from bromocriptine, this drug is worth a trial in patients not doing well on levodopa therapy if other means to improve their condition are not successful.