The purpose of this study was to identify traumatic experiences of undergraduate students and to verify symptoms of Post-Traumatic Stress Disorder(PTSD) and degree of distressed psychological impact by the traumatic experience. A total of 624 of undergraduate students in Seoul, Busan and Kyeongnam province participated in this study. As a result, approximately 97.9% of participants reported that they experienced at least one traumatic event in their life, and it appeared that the frequencies of traumatic event rated 6.7 for male and 6.6 for female. It has been also reported that the most distressed traumatic events were‘Death of family or relatives’,‘Problems of interpersonal relationship(dispute, conflict, quarrel, separation, parting etc.)’,‘Dispute or conflict with family members’,‘Difficulties in adaptation(school, society, marginalized in the army, bullying, experience of verbal and physical violence etc.)’,‘Academic failure(failures in important subjects and examination)’, in this order. Among all participants, 37.1% were classified as potential full PTSD group, 11.8% were potential partial PTSD group. The types of traumatic experiences which cause potential full PTSD were‘Sexual harassment and sexual assault’,‘Serious physical illness of self’,‘Problems of interpersonal relationship(dispute, conflict, quarrel, separation, parting etc.)’,‘Arrest(self and family members)’,‘Divorce of separation(parent)’. The differences in PTSD symptoms according to sociodemographic variables revealed showed significance in residence type(e.g., living with parents, living alone) only. Lastly, the significance and limitations of this study were discussed.