Abstract—Social media has become part of daily life of society in Indonesia, so it is used by business actors to promote their products, with the purpose of advertising messages delivered can be disseminated to others and become viral so as to increase awareness of the product and purchase decision. So the purpose of this study is to know how the impact of social media in creating viral marketing and its impact on Brand Awareness and purchase decision. Data collection techniques used were questionnaires distributed to 150 respondents of social media users then analyzed by using SEM. The results of this study indicate that the use of social media in viral marketing can increase Brand Awareness of the product and purchase decision. Keywords—component; Viral Marketing; Brand Awareness; Purchase Decision; Social Media Instagram