Sixteen parkinsonian patients, mean age 57 (range 41-71), with a mean 9 year duration of Parkinson's disease, with "on-off" motor fluctuations were treated with pergolide mesylate 1.6 mg/die (range 1-5) for three months. The treatment resulted in an improvement of akinesia, tremor and rigidity, of the severity of phase "off" and of the duration of time "on". No significant improvements were obtained in the severity of dyskinesia. Three patients considered the treatment excellent and capable of restoring their working abilities. The drug was generally well tolerated. Pergolide was discontinued because of orthostatic hypotension in two patients and because of hallucinations in one patient. We consider these results a favorable progress in the treatment of Parkinson's disease.