With the rise of social media and the emergence of smartphones, new possibilities have arisen for companies to create and maintain customer relations. Today, customers expect companies to be represented on social media platforms. Customers today will discuss companies and products on social media, regardless of whether the companies are represented on the platforms or not. Therefore, it is important for companies to be present on these platforms in order to be a part of the discussion. On Instagram, a company can share content that would perhaps be unfitting for any other medium. This thesis researches how the top five Interbrand companies on Instagram have worked with marketing and PR, and how their posted content affects the users’ level of interaction.    Two methods of analysis have been used in the writing of this thesis. In the first one, content analysis, the content and level of interaction of 200 Instagram posts were examined. Furthermore, a survey was conducted, with the aim of investigating Instagram users’ motivations for using the platform and of following a company profile on Instagram.   The material has been researched with an overall marketing and public relations perspective. Other theories that have been used concern customer relationship management, self-representation and self-disclosure, back stage and front stage and word-of-mouth theories.   The results show strong indicators that different kinds of posts evoke different levels of user interaction. The companies mainly use Instagram to market their products and to share information about events and new releases. These kinds of posts mainly receive a low level of interaction, with as little as one percent of the companies’ followers liking, and two in 10 000 commenting on the pictures. However, when the companies utilized Instagram’s co-creative features, for example by encouraging the users to use company specific hashtags, the level of interaction increased by as much as five times. Other interesting results concern back stage sharing and how interaction affects trust in a company’s message.