AIM The aim of this study was to assess the results of unilateral subthalamic nucleus (STN) stimulation for the treatment of Parkinson"s disease (PD) with marked asymmetry of parkinsonian motor symptoms and early motor complications. MATERIAL AND METHODS The clinical series consisted of 32 consecutive PD patients, in whom unilateral STN stimulation was performed. All patients were assessed according to the Unified Parkinson"s Disease Rating Scale (UPDRS), and Hoehn and Yahr staging. The patients were assessed preoperatively, and at 12, and 24 months after unilateral STN stimulation. 22 patients were followed for 2 years. RESULTS Medication off/stimulation on total UPDRS motor scores were improved by 29% when compared to the baseline medication off motor scores. The contralateral motor scores improved by 49%, whereas the axial motor scores by 18% in medication off/stimulation on condition. The duration and severity of levodopa induced dyskinesia were reduced respectively by 73% and by 77%. The daily levodopa dose was decreased by only 10%. CONCLUSION Unilateral STN stimulation is a safe and effective procedure for selected patients with marked asymmetry Parkinson"s disease motor symptoms and early motor complications.