Background: ‘Differentiation of self’ is an important factor for a person to cope with stressors and improve mental health. Therefore, it is necessary to provide appropriate instruments to assess this construct. Objectives: The present research aims to study the psychometric properties of the Differentiation of Self Inventory - Short Form as an appropriate instrument for assessing differentiation of self in the Iranian society. Method: After translation and adaptation of the questionnaire, 384 undergraduate students at Shiraz University who were selected using random multi-stage sampling method, responded to it. The instruments used in this study consisted of Differentiation of Self Inventory-Short Form (DSI-SF) and General Health Questionnaire (GHQ). Results: The results of factor analysis showed that the structure of this questionnaire clearly referred to the four factors of differentiation including fusion with others, emotional cut-off, emotional reactivity, and I-position. Face validity was confirmed by experts, and correlation coefficient of each component with the total score was significant. Moreover, the significant negative correlation between DSI-SF scores and somatic symptoms, anxiety/insomnia, social dysfunction, and depression scores was indicative of concurrent criterion validity. For the validity of scale, Cronbach's alpha coefficient was desirable. Conclusion: The results of showed that the validity and reliability of DSI-SH is qualified for assessing the differentiation of self, and that it can be used as a useful instrument for assessing the differentiation of self in the Iranian society.The role ofculture was also discussed in this study.