Purpose: This study was conducted to investigate the incidence and associated factors with post-traumatic stress disorders (PTSD) in patients with intensive care units (ICU) admission experience. Methods: This study is a retrospective observational study using self-reporting questionnaire. Patients who were admitted to ICU more than 72 hours and agreed to participate were enrolled in this study. PTSD were assessed by Korean version of post-traumatic diagnosis scale, and PTSD was defined as 20 points or more. Medical records of participants were reviewed to identify influencing factors of PTSD. To analyzed the data, descriptive statistics, Mann-Whitney U test, Kruskal-Wallis test and gamma regression were utilized using SPSS/WIN 23.0 program. Results: A total of 128 patients participated in the study. Mean age of participants was 58.3±11.7 years and 50 patients (39.1%) were female. Mean duration of ICU stay was 8.43±8.09 days and PTSD was diagnosed in 12 patients (9.4%). In the results of a Gamma regression analysis, Psychiatric history (B=1.09, p=.002), APACHEII score (B=.04, p=.005), CPR experience (B=1.65, p=.017) and physical restraint (B=.68, p=.049) were independently associated with PTSD occurrence. Conclusion: The results of this study suggest that a various factors influencing PTSD should be identified to prevent PTSD in patients who requires ICU care. In addition, post-ICU care programs are required to assess and reduce PTSD.