The present study is applied research to identify the relationship between the amount and type of Instagram use with the level of social vitality of young people in Tehran. The theoretical framework of this study is a combination of use and satisfaction theory and Diner's theory of social vitality. This research is of quantitative type and its survey method. The statistical population of all youth in Tehran is 1937064 according to the latest census. The sample size is 384 people, and the cluster sampling method is multi-stage. The technique of collecting questionnaire information and data analysis was done through SPSS software. Validity of face validity and reliability were calculated through Cronbach's alpha coefficient, which was 0.88 (88%) for the variable of Instagram usage and 0.82 (82%) for the variable of social vitality. According to descriptive findings, the average use of Instagram by young people in Tehran during the day was 3 hours and 39 minutes, which is ranked first compared to other social networks. Most of their use of Instagram is cognitive. Also, the level of social vitality in the Likert scale is five degrees on average. Among the dimensions of social vitality, the most vitality with 3.6 (in the 5 Likert range) belongs to the social dimension. The results show that there is a significant correlation between social vitality and the amount of Instagram use. This correlation is inverse, and its intensity is weak. Regarding the relationship between the type of Instagram use and the level of social vitality, we can say that there is an inverse correlation between the type of entertainment and recreational use, gaining personal identity, getting to know others, and communicating with others with social vitality. The findings also showed that there is a direct correlation with low intensity only in terms of obtaining news and information and the level of social vitality. In general, it can be said that with the increase in the use of Instagram among young people, their social vitality was weakly reduced. In the type of use of Instagram, as the use of entertainment and personal identity increased, the social vitality of the youth of Tehran decreased. Also, among the dimensions of social vitality, the most negative correlation was on security vitality.