In eight patients with advanced Parkinson's disease, we performed autograft transplantation of adrenal medulla to the head of the caudate nucleus. Our technique was similar to that developed by Madrazo and co-workers in Mexico City. No major perioperative complications occurred except for somnolence in one patient for 8 days postoperatively. The follow-up period has been at least 6 months in seven of the patients, and only limited benefit has been apparent. The early morning Parkinson examination score in the "off" (unmedicated) state was significantly improved in one patient and slightly better in the other six. Diary card entries suggested a mild trend toward improvement (not statistically significant). Four of the seven patients were taking less levodopa 6 months after the operation than they had been preoperatively; three of five patients were no longer taking dopamine agonists postoperatively. We cannot exclude a placebo effect contributing to any of this improvement. A reduction in medication-induced dyskinesia was also noted, but this result may have been due to adjustments in doses or a slightly less potent effect of medication (or both factors). In summary, we have not yet been able to replicate the dramatic success reported for adrenal medullary transplantation by Madrazo's group, although our patients may have experienced mild to moderate improvement. We continue to maintain follow-up surveillance of these patients.