Obsessive-compulsive disorder (OCD) is a common psychiatric disorder characterized by disturbing thoughts, mental pictures (obsessions), and repetitive behaviors (compulsions). Despite the current utilization of pharmacologically selective serotonin reuptake inhibitors (SSRIs) and cognitive-behavioral therapy, persistent symptoms are reported in 40-60% of patients. Hence, we aim to analyze the levels of specific miRNAs and comprehensively evaluate the levels of serotonin, a pivotal neurotransmitter in the context of OCD. In the present study, blood serum was taken from peripheral whole blood samples of 22 patients with OCD and 20 healthy people with no diagnosis. Total RNA was isolated from the serum samples and quantitative real-time PCR was performed for target miRNAs. Snord44 was used as a reference gene. Additionally, serotonin levels in serum were evaluated by ELISA. In the OCD group, serotonin levels were found to be significantly higher than that of the controls (p= 0.0457). Although mir-21-5p expression was found to be higher in the OCD group, it did not reach statistical significance. However, the gene expression levels of mir-132 (p=0.006) and mir-125b-5p (p<0.0001) were found to be significantly different in the OCD group compared to the controls. In conclusion, we observed that miRNAs affecting genes prominent in OCD were found to be different from the healthy controls. It is promising to use these identified target miRNAs as biomarkers in the diagnosis of diseases in the future and may shed light on the background of the disease.