This paper deals with social networks in sports as a means of market communication. Throughout this paper it is determined that social networks nowadays are irreplaceable marketing tool and that they have big role in a business of every sports club. Through them, it is possible to conduct various marketing activities and sports marketing. Clubs use them for announcing sports events, promotional offers, prize games, sharing photos and videos from matches, communicating with fans, etc., all with the aim of keeping existing and attracting new fans and creating loyalty. This leads to more reactions to activities on social networks, which leads to an increase in the popularity of a brand or a sports club. As a final result there is an increase in the consumption of sports goods, i. e. increased club revenues. It was also found that sports clubs should carefully select the social network they are going to use, and if they use more of them, the content they share should not be the same. Numerous examples of use of social networks in sport are outlined in this paper, and football club Juventus has been analyzed in detail, which confirms the importance of social networks in sport. Performance on social network Facebook is rated as good, however, there is still room for improvement. Therefore, recommendations were made, that mostly relate to increased publishing frequency, linking Facebook's site to other sites, and inviting fans to interact.