Background and Aim: The aim of this study was validation of questionnaire of psycho - social aspects (PSA) of phone-based social networks' (MSN) use.

Methods: This descriptive survey used a researcher-made questionnaire on a sample of post graduate students of University of Birjand and Persian Gulf University (348 participants).

Results: For questionnaire’s validity, the experts’ opinions and factor analysis were used, and Cronbach's alpha was used for questionnaire’s reliability (0.87). Finally, According to the results of the initial test, compensation and socialization, and self-presentation and virtual self were combined to form 4 factors of "information behavior", "addiction", "socialization and compensation" and "self- presentation and virtual self" as final questionnaire’s factors. After removing items that had no suitable loading on any factors and also with no theoretical and logical justifications, out of 47 items 35 remained.