We treated 36 patients with motor fluctuations and dyskinesias on chronic levodopa therapy with cabergoline (CBG) once a day for a mean period of 14.2 ± 5.8 months. There was a significant increase in the “on” hours and a reduction in “off-period” dystonia. Ten patients continued to show a marked improvement after 28.3 months of treatment (mean dose, 11.3 ± 4.5 mg). In 23 patients, increased dyskinesias (daily CBG dose, 11 ± 4.3 mg) had complicated the positive effect after 17.2 ± 4.8 months. Three patients (daily CBG dose, 14.3 mg) were therapeutic failures, and administration of CBG was stopped. Side effects leading to CBG discontinuation were visual hallucinations (n = 5), heart failure (n = 5), and nausea and vomiting (n = 1). Plasma CBG levels, measured in seven patients taking 3, 5, or 7 mg daily (po), showed fairly stable concentrations throughout the 24 hours. We concluded that CBG is an efficient dopamine agonist that can provide continuous dopaminergic stimulation when taken orally once a day.