Objective: Deep brain stimulation (DBS) intended to bilateral subthalamic nucleus (STN) used in the Parkinson’s disease (PD) has been reported to lead improved subjective sleep quality, increased sleep efficiency, decreased wakefulness time after sleep, and increased total sleep time. On this basis, we aimed to evaluate the sleep structure and quality by polysomnographic (PSG) investigation parameters in patients diagnosed with idiopathic PD who were planned to undergo bilateral STN-DBS. Materials and Methods: Inclusion criteria were determined as the presence of a clinical diagnosis of idiopathic PD, being 70 years and below, having at least 5 years of disease duration, and being a suitable candidate for STN DBS surgery. Patients were excluded from the study in the presence of dementia or psychiatric disturbances, cardiac pacemaker, and history of cerebrovascular disease. Our study was approved by Local Ethical Committe of Istanbul University-Cerrahpaşa, Cerrahpaşa Faculty of Medicine, and signed consent form was obtained from participants. Results: Eight patients were included in our study; the mean age was calculated as 53.6±4.1 years. When pre- and postoperation PSG parameters were compared, the total sleep time was decreased, however it was not found statistically significant (p=0.840). REM sleep latancy was significantly shortened postoperatively (p=0.003). It was observed that other PSG parameters measuring the macro- and micro-structure of sleep did not change significantly (p>0.050). Conclusion: Many studies have reported substantial improvements in parameters obtained by polysomnography, while only one study has reported that sleep was not normalized although subjective sleep quality was increased. In our study, except for shortening in the REM sleep period, no significant improvement in PSG parameters was observed. The effect of bilateral STB-DBS on sleep is still one of the controversial issues and waits to be demonstrated in the larger series.