Effects of brief Behavioral Relaxation Training (BRT) on anxiety and dyskinesia of a 57-year-old female, with an 11-year history of Parkinson's disease (PD) and 18-months post-deep brain stimulation of the subthalamic nucleus, were evaluated. Multiple process and outcome measures were used including the Clinical Anxiety Scale (CAS), Subjective Unit of Distress (SUD) rating and Abbreviated Treatment Acceptability Rating Profile (AARP). An A-B single-case research design with a six week follow up was used to the evaluate effectiveness of intervention. BRT resulted in systematic increases in relaxed behavior and decreased SUD ratings in vivo and decrements in CAS scores. Results were maintained at follow up. The participant rated BRT as highly acceptable. Use of single-case research design enabled objective evaluation of intervention effects. Due to the heterogeneity of PD patients, single-case experimental designs are especially valuable for evaluation of treatment effectiveness and technique building with this population. Finally, findings suggest that BRT is a valuable adjuvant behavior therapy intervention for patients with anxiety and dyskinesia related to Parkinson's disease. Further research regarding BRT and Parkinson's disease-related disability are indicated.