This volume contains the proceedings of the 7th International Symposium of Frontiers of Combining Systems (FroCoS 2009) held during September 16-18, 2009 in Trento, Italy. Previous FroCoS meetings were organized in Munich (1996), Amsterdam (1998), Nancy (2000), Santa Margherita Ligure (2002), - enna (2005), and Liverpool (2007). In 2004, 2006, and 2008 FroCoS joined IJCAR, the International Joint Conference on Automated Reasoning. Like its predecessors, FroCoS 2009 o?ered a forum for the presentation and discussion of research activities on the combination, integration, analysis, m-...