Objectives:To determine the serum expression levels of seven candidate microRNAs (miRNA); miR-19a, miR-19b, miR-29a, miR-29c, miR-181, miR-195 and miR-221 in Turkish patients with Parkinson's disease (PD) and explored their potential role in the diagnosis of PD. We further described the relationship between these miRNAs with the clinical findings and treatment of PD. Materials and methods:The study included 51 PD patients and 20 healthy controls. The clinical severity of disease was assessed using the Hoehn Yahr staging scale and the Unified Parkinson's Disease Rating Scale (UPDRS). Venous blood samples were taken after fasting for 12 h, then centrifuged. Obtained serum samples were stored until analysis of miRNA. In the laboratory, expression levels of these miRNAs were analyzed using a real-time PCR instrument. Receiver-operating characteristic analysis and area-under the-curve (AUC) was used to evaluate these miRNA levels as potential diagnostic biomarkers for PD. Results:miR-29c expression levels were increased significantly for PD patients compared to healthy controls. There were no significant differences in levels of other miRNAs between PD patients and controls. The AUC of miR-29c was 0.689. The sensitivity and specificity of this diagnostic test was 54.9% and 80.0%, respectively. miR-195 level was found to have a significant positive correlation only with age. Significant negative correlation was found between miR-29a level and UPDRS total score. miR-19b was found higher in ropinirole drug used group than that of pramipexole group. Conclusion:This study suggests that serum miR-29c expression level might be potential biomarker in the diagnosis of Turkish Parkinson patients.