This volume contains 31 peer-reviewed papers based on the presentations at the 7th International Annual Workshop on Bioinformatics and Systems Biology (IBSB 2007) held at the Human Genome Center, Institute of Medical Science, University of Tokyo from July 31 to August 2, 2007. This workshop started in 2001 as an event for doctoral students and young researchers to present and discuss their research results and approaches in bioinformatics and systems biology. It is part of a collaborative educational program involving leading institutions and leaders committed to the following programs and partner institutions: Boston (Charles DeLisi) - Graduate Program in Bioinformatics, Boston University; Berlin (Herman-Georg Holzhutter) - The International Research Training Group (IRTG); "Genomics and Systems Biology of Molecular Networks"; and Kyoto/Tokyo (Minoru Kanehisa/Satoru Miyano) - Joint Bioinformatics Education Program of Kyoto University and University of Tokyo.This volume is dedicated to the memory of Prof. Dr. H.C. Reinhart Heinrich, a former Professor at Humboldt University Berlin and a co-founder of this workshop.