Preface A U.S. Geological Survey Interdisciplinary Microbiology Workshop was held in Estes Park, Colorado, on October 15-17, 2008. Participants came from all USGS regions and disciplines. This report contains abstracts from 36 presentations and 35 poster sessions and notes from 5 breakout sessions. The seven presentation topics follow: Ecology of wildlife and fish disease Mechanisms of fish and wildlife disease Microbial ecology Geographic patterns/visualization Public health and water quality Geomicrobiology Ecosystem function The six poster session topics follow: Wildlife disease Disease detection methods Water quality Microbial ecology Metabolic processes Tools and techniques Five working groups met in breakout sessions on October 16, 2008. The highlights for each working group are summarized in this report, and their goals are listed below: Working Group I: to plan a Fact Sheet on interdisciplinary microbiology in the USGS Working Group II: to plan a USGS interdisciplinary microbiology Web site Working Group III: to suggest ways to broadcast and publicize the types of microbiology conducted at the USGS Working Group IV: to identify emerging issues in USGS interdisciplinary microbiology research Working Group V: to identify potential opportunities for interdisciplinary microbiology work at the USGS After the workshop, the USGS interdisciplinary microbiology Web site was activated in June 2009 at http://microbiology.usgs.gov/.