After the stereotactic treatment of patients with Parkinson's disease, a correlative study between the site of the deep subcortical lesions and subsequent cerebellar signs (dysmetria and hypotonia) was made. Cerebellar signs appeared in 27 cases (40.8%) of subthalamotomy and in 3 cases (8.6%) of VIM thalamotomy 2 weeks after an operation. The appearance of these signs after an operation was independent from the operative effect on tremor. Thus, we concluded that VIM thalamotomy might be better than subthalamotomy for the relief of tremor in Parkinson's disease.