Undoubtedly, the social world is changing and one of the main factors of transformation in the current world is new and modern technological achievements which are considered as modern media. However, due to their emerging nature of these media, there has been no agreement on their positive or negative effects and there have been different ideas about the effect of these modern media such as virtual social networks such Cloob on social capital. In addition, regarding the available statistics, the most use of virtual social networks is assigned to the youth particularly young girls and women who use these networks with different types of motivation. The study of the effects of using virtual social networks among girls and women can identify some consequences of these modern media. The present study was conducted using a survey research and employing a researcher-made internet-based questionnaire whose reliability was confirmed using Cronbach’s alpha coefficient as 0.79. Research population includes all girls and women who are members of Cloob Social Network in Tabriz. The theoretical framework of the research is extracted from available theories about effects of virtual spaces on social capital. Research findings indicate that there is a direct and significant correlation of variables of the duration of users’ membership in Cloob, the degree of using Cloob, the degree of participating and being active in Cloob, and the degree of significance of Cloob for users with the degree of social capital. In addition, independent variables entered the regression model of the research could explain 30% of variations of participants’ social capital. In general, the results indicate that Cloob Social Network can increase users’ social capital. تفاصيل المقالة