Background: Chronic pain is a burdensome symptom. Different psychological models have been proposed to explain the role of psychological and social factors in developing and maintaining chronic pain. Attachment is a psychological construct of possible relevance in chronic pain. Aims: The aim of the present study was to examine the effect of predicting attachment styles on pain catastrophizing in patients with chronic pain. Methods: In a descriptive-correlational study, convenience sampling was used to select 120 chronic pain patients from pain clinic of akhtar hospital in Tehran, Iran during three months. The participants completed a demographic questionnaire, Adult Attachment Inventory, Pain Catastrophizing Scale. Data was analyzed using Pearson's correlation and step by step regression models. Results: The correlations between attachment styles & depending variables in this study were significantly (P<0/01). Based on the results of regression analysis, secure and ambivalent attachment styles was able to predicted pain catastrophizing in patients with chronic pain. Conclusion: According to the results of the present study, it can be concluded that secure and ambivalent attachment styles can predict pain catastrophizing. Considering these variables may be important in the processes of prevention, diagnosis and treatment reparation of attachment, as well as promoting mental health in patients with chronic pain.