The goal of this study was to determine whether unilateral pallidotomy reduces parkinsonian pain. Twenty-one patients suffering from Parkinson's disease (PD) were followed prospectively for 1 year after they had undergone a unilateral pallidotomy to assess the procedure's effect on pain related to PD. Pain unrelated to PD was not studied. Patients scored the level of their PD pain on an ordinal scale (0-10 points) preoperatively and 6 weeks and 1 year postoperatively. The results were analyzed using Wilcoxon's paired-ranks test (with Bonferroni correction) and showed a significant reduction in overall pain scores at 6 weeks (p < 0.001) and 1 year (p = 0.001) following pallidotomy. Various types of PD pain are described and their possible pathophysiological mechanisms are presented. Unilateral pallidotomy significantly reduces pain attributable to Parkinson's disease.