Background: Adverse childhood experiences (ACEs) have a negative effect on adolescent personality traits and are linked to poorer physical and mental health. The present study aim   to investigate the relation between childhood negative experiences and personality traits among Port Said university students. Subjects and Methods: Design: A descriptive correlation design was utilized. Setting: The study was carried out across all 13 faculties at Port Said University. Subjects: A purposive sample of 716 students from all faculties was included in the study. Tools: Two tools were used for data collection:  (1) questionnaire sheet to assess negative childhood experiences, (2) The Big Five Inventory to measure the Big Five dimensions of personality traits (Extraversion, Agreeableness, Conscientiousness, Neuroticism and Openness) in addition to personal characteristics of the studied sample. The Results: there were statistically significant negative correlation between total score of childhood negative experiences and extraversion, agreeableness, conscientiousness and openness personality. While, there was a statistically significant positive correlation between total score of childhood negative experiences and neuroticism personality. Conclusion: It can be concluded that, near to a half of the studied sample had average negative childhood experiences and approximately a half of the studied sample had a neuroticism personality traits. Recommendations: The study recommended that, designing and implementing an intervention program include parenting education to teach coping strategies to change maladaptive pathways to avoid negative childhood experiences which affect negatively on the personality traits.