Nowadays social networks are used more than ever. Except for private purposes, they are often used in the business environment. Many non-profit organizations communicate with the public through social networks. They have become an indispensable part of the business because they greatly facilitate communication, provide quick feedback and target the target segment of the organization precisely and successfully. Social networks are web based services that allow an individual to create a (semi) public profile within a restricted system, formulate a list of other users with whom they share a connection, and view lists of contacts and those lists made by other users within the system. They are of particular interest to non-profit organizations because they provide excellent advertising results with minimal investment. Since non-profit organizations operate for the purpose of pursuing a particular public interest rather than profit, it is very important for them to keep the costs low, in which social networks help them. The aim of thesis is to point out the importance of using social networks in the business of the non-profit sector, and to explore further possibilities of this relatively new tool in advertising and communication of non-profit organizations. Qualitative research methodology was applied in the thesis. A focus group interview was conducted with four employees of association Vestigium. The results of the research show that social networks have a positive impact on the business of the association, allowing greater transparency, interest and community connection. Social networks can truly contribute to the recognition, sustainability and success of non-profit organizations.