As genome-sequencing costs continue their downward spiral, sequencing of closely related organisms has become increasingly a?ordable. The growing amount of genomic data available demands for the constant development of computational tools to be applied in comparative genomics. The RECOMB Workshop on C- parative Genomics (RECOMB-CG) is devoted to bringing together scientists working on all aspects of comparative genomics, from computer scientists, ma- ematicians and statisticians working on novel computational approaches for genome analysis and comparison, to biologists applying these computational tools to study the structure and the evolution of prokaryotic and eukaryotic genomes. This volume contains the 19 papers presented at the 7th Annual RECOMB-CG workshop held during September 27–29, 2009 at the Renyi Institute, in Budapest, Hungary. The papers published in these proceedings were selected for oral p- sentation from 31 submissions from scientists around the world. Each paper was reviewed by at least three members of the Program Committee in a stringent and thoughtful peer-review process.