Background: The aim of this study was to investigate the relationship of attachment styles (secure, avoidant, anxious-ambivalent) and five factor personality traits (neuroticism, extroversion, openness to experience, agreeableness and conscientiousness) with homesickness among the trainees of one of the non-commissioned police officer training centers. Materials and Methods: The present research was a cross-sectional descriptive study conducted in 1392 on 300 people of trainees in one of the non-commissioned police officer training centers. Participants were selected by stratified random sampling. The instruments of this study were: 1) five factor personality inventory 2) Simpson attachment style inventory 3) Van Viet homesickness scale. Data were analyzed by descriptive statistics, Pearson's correlation coefficient and linear regression analysis through SPSS 16. Results: Anxious-ambivalent attachment style and neuroticism had the most significant positive correlations with homesickness. Also, regression analysis represented that anxious-ambivalent attachment style, neuroticism, openness to experience and agreeableness were able to predict homesickness. Conclusion: Based on the results of this study, it is proposed that more surveys be performed about relationship between secure attachment style and adjustment disorders in military setting. It is also proposed that neuroticism and anxious-ambivalent attachment style be considered as negative factors and conscientiousness be considered as a positive factor in the selection of personnel of NAJA.