Aim: The purpose of this study was to investigate the relationship between self-differentiation and alexithymia and addiction tendency in medical students.

Materials and Methods: This descriptive correlational study was conducted in male and female students of Birjand University of Medical Sciences during the 2014-15 academic year and 337 students were selected by random cluster sampling method. In order to collect information, Scorner & Frederlinder self-differentiation, Toronto alexithymia and Qorbani addiction tendencies questionnaires were used. Data were analyzed using multiple stepwise regression analysis.

Results: self-differentiation and its components (my position and emotional responsiveness) as well as alexithymia and one of its component (difficulty in identifying emotions) predicted addiction tendency in students (p<0.001).

Conclusion: Regarding the role of alexithymia and self-differentiation in predicting addiction tendency in students, the necessity of the attention of authorities, planners and administrators of educational system in order to reduce alexithymia and improve self-differentiation through workshops is necessary.