A relatively simple method for implanting fetal tissue within the human basal ganglia is described. Stereotactic techniques are used to deposit 14 to 16 strands of fetal mesencephalic tissue in a linear array within the putamen bilaterally. To eliminate the need for targeting each needle pass independently, we have devised a novel rotating template/micromanipulator apparatus that can be mounted on a Cosman-Roberts-Wells stereotactic frame. The template contains two parallel columns of nine holes, all spaced at 4-mm intervals. It can be aligned to the longitudinal axis of the putamen and targeted with coordinates for the center point of the putamen. Surgery is performed on an awake patient. Short-term morbidity (4-6 wk) in the form of variability of Parkinsonian signs, particularly "off" symptoms and mild confusion, appears to be the rule with simultaneous bilateral implants.