Social media are one of the most flexible and dynamic tools of the Internet, which stems from the fact that they offer bidirectional communication. They enable banks to individualize the process of marketing communication and conduct the kind of communication with clients on the market that resembles a dialog. The aim of this article is to identify social media in the marketing communication of banks in Poland. This article presents the essence of these media to subsequently focus on the role of social media in the activity of banks. It also verifies the scope of using social media by major banks. Further, it analyzes the contents of websites and social media profiles of the banks included on „The 500 List” („Lista 500”) of the largest Polish businesses. The list features 19 banks. This particular ranking has been applied due to the fact that large banks often pioneer the implementation of new methods of communication, including the use of social media. They also have appropriate resources to conduct communication activities on a large scale. The results of the analysis of website contents and social media profiles of banks have been presented in the article.