Tehran University of Medical Sciences Iranian Journal of Psychiatry 1735-4587 9 3 2014 09 15 147 51 Mohammad Reza Mohammadi Tehran University, of Medical Sciences, Psychiatry & Psychology Research Center,Tehran, Iran Morteza Shamohammadi Tehran University, of Medical Sciences, Psychiatry & Psychology Research Center,Tehran, Iran Maryam Salmanian Tehran University, of Medical Sciences, Psychiatry & Psychology Research Center,Tehran, Iran 2015 10 14 Objective: This study aimed to assess the prevalence of borderline personality symptoms in 16-18 year old adolescents. Methods: In this cross sectional – descriptive study, 422 high school students (211 boys, 211 girls) aged 16-18 were selected by cluster random sampling and simple random sampling in 2011-2012. The participants were assessed using the revised diagnostic interview for borderline questionnaire (DIB-R) and demographic questionnaire. Data were analyzed using Pearson correlation coefficient and Spearman correlation coefficient. Results: Of the participants, 0/9% (0/22 % of the 16 year olds, 0.45 % of the 17 year olds and 0/22% of the 18 year olds) were diagnosed with borderline personality symptoms. Also, the prevalence of borderline personality symptoms in boys was 0/45 % of the total sample and it was 0/45 % of the total sample in girls. With respect to the relationship between demographic variables (age, sex, location, parents’ occupation, parents’ kinship, parents’ education and birth order) a d borderline personality symptoms, only parents’ kinship showed a weak correlation with borderline personality symptom  . Conclusion: In the view of the prevalence of 0.9% of the borderline personality symptoms in adolescents, attention should be paid to the diagnosis and treatment of this disorder. Furthermore, works need to be done to improve the mental health and quality of life of adolescents. https://ijps.tums.ac.ir/index.php/ijps/article/view/51 https://ijps.tums.ac.ir/index.php/ijps/article/download/51/47