The purpose of this paper is to explain and demonstrate the importance of social networks in corporate communication based on relevant Croatian and international literature. For a better and more efficient description online communication has been analyzed on social networks within five corporations: Croatia Airlines, INA, Lidl Croatia, Zagrebačka banka and Vipnet. Mentioned corporations were selected based on total number of users on the social networks in the period from 15 May 2017 to 15 June 2017. The results of the analysis show that social networks are an excellent platform for promoting products and services and getting closer to the targeted public. Social networks in comparison to traditional media offer two-way communication which can be a benefit and risk to the corporation. In order for the strategy to be successful, it must be fun because it will also be more interaction, and thus will will reach a large number of new users. In order for the strategy to be successful, it must be fun, because it that wiil provide more interaction and therefore new fans. It is also desirable to have a business measure to attract new customers. The paper is divided into five chapters. The first chapter will be about concept of public communication, new media and the Internet. The second chaptere focuses on public relations, the public relations service, and the public relations agency. The third chapter deals with corporate communications and social networks in corporate communications. The fourth section deals with social networks and community management. The last chapter brings the analysis of the social networks of five corporations.