Objective: This study was conducted to determine the role of therapeutic alliance and attachment styles in the prediction of treatment drop-out. Method: A descriptive-correlational method was used for the conduct of this study. A total of 234 men with substance abuse presenting to the clinics and treatment centers of Tehran were selected through purposive sampling. In case of the enjoyment of the inclusion criteria, these subjects were interviewed and filled out the research instruments, including Working Alliance Inventory/Short (WAI-S) and Adult Attachment Inventory. Results: Logistic regression analysis showed that therapeutic alliance and attachment styles can distinguish people dropped out of treatment and people continuing treatment. Conclusion: These findings, consistent with previous studies, indicate the role of variables pertaining to interpersonal relationships in the treatment drop-out of patients with substance abuse.