Purpose: Recently, oxytocin has been introduced experimentally as a pharmacological treatment for post-traumatic stress disorder(PTSD). This study attempted to investigate the possibility of oxytocin as a treatment option for patients with PTSD by examining itsdose, interval, and effectiveness in patients with PTSD. Methods: A systematic review was done on articles published from 1967 to2020 using the PubMed, PsycINFO, and Cochrane databases. Our inclusion criteria were 1) subjects 18 years of age or older diagnosedwith PTSD or exposed to a traumatic event that met criterion A of the Diagnostic and Statistical Manual of Mental Disorders (DSM) forPTSD, 2) oxytocin was administered at least once, 3) clinical trials, and 4) studies published in Korean or English. Two independent researchersreviewed 22 articles and recorded the contents. The risk of bias was evaluated to determine the quality of the reviewed article. Results: The parameters for evaluating the effectiveness of oxytocin were identified as socio-behavioral measures in 11 articles,neuronal imaging in 9, and biomarkers in 4. In 5 papers, oxytocin was administered multiple times. Socio-behavioral measures wereimproved in 3 out of 5 studies in which oxytocin was administered multiple times. In 2 studies in which prolonged exposure treatmentand nasal oxytocin administration were combined for 10 weeks, patient symptoms were decreased compared to the controlgroup. Conclusion: The possibility of oxytocin as an adjuvant treatment for PTSD psychotherapy was confirmed. Further studies arenecessary to evaluate the long term effectiveness of administering oxytocin multiple times combined with psychotherapy.