To examine the effects of autologous sural nerve and adrenal medullary tissue intrastriatal cografts upon voluntary motor performance in parkinsonism, a non-human primate 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model was employed to quantitatively assess skilled hand movements. Motor performance was studied in normal, MPTP-induced parkinsonian, and then cografted states. Reaction and movement times were prolonged and variability increased in experimental and control animals in the parkin-sonian state. Animals undergoing autologous cografts demonstrated improved motor performance whereas the control animal continued in a chronic, stable parkinsonian state. Intrastriatal-cografts of autologous adrenal medullary tissue and sural nerve resulted in good to excellent chromaffin cell survival. The mechanism of the restoration of function in the cografted monkeys remains to be determined. © 1995.