Web 2.0 and social media applications are popular communication channels and are frequently utilised by individuals and organizations in many sectors and markets. While they are widely recognised as having good potential for reaching large population segments in an efficient way, little is known about their effectiveness in influencing behaviour change. The aim of this paper is to analyse the available literature, examining papers that report outcomes associated with social media used in health communication initiatives. Specifically, it aims to under- stand what topics are being addressed, what types of social media are used, what types of outcomes are measured, and if they are effective in changing health behaviours. A scoping review was conducted for papers published from January 2005 to May 2010. Twenty-three papers reported outcomes of health communi- cation initiatives using social media. Findings suggest that more research isolat- ing the effects of social media on health-related behaviours is needed.