We treated 12 patients with Parkinson's disease with an 8-alpha-amino-ergoline derivative, CU 32-085. The daily dosage was increased slowly to 7 mg over 9 weeks, held constant for 8 weeks, then replaced by placebo for 4 weeks. We found statistically significant benefit over placebo or pretreatment disability. The effect was seen at daily dosages of 3 mg or more. Its magnitude was dose related. There was no further improvement on prolonged treatment with 7 mg daily. Side effects were mild and did not require interruption of treatment.