This book constitutes the refereed proceedings of the International Workshop on Biosurveillance and Biosecurity, BioSecure 2008, held in Raleigh, NC, USA, in December 2008. The 18 revised full papers presented together with one invited paper were carefully reviewed and selected from numerous submissions. The papers are organized in topical sections on informatics infrastructure and policy considerations; network-based data analytics; biosurveillance models and outbreak detection; model assessment and case studies; environmental biosurveillance and case studies.