A Laboratory Response Network is imperative to the U. S. Defense Department, homeland security, and mission preparedness. It provides improved confirmatory and definitive agent identification, as well as enhancing the availability of referral testing facilities, ensuring consensus on protocol, procedure, and result reporting, provide consultation, and define information flow. This paper briefly describes a Laboratory Response Network which includes both private and public facilities. This network offers laboratory workers across the United States and overseas a formal defense mechanism to access a variety of test procedures, protocols, scientific experts, and bioterrorism consultants. Partners involved in the Laboratory Response Network include, but are not limited to, Department of Health and Human Services, Centers for Disease Control and Prevention, U.S. Army Medical Research Institute of Infectious Diseases, Department of Energy, Federal Bureau of Investigation, and the American Society for Microbiology. The U.S. laboratory network is comprised of four laboratory classifications based on capabilities, levels A through D. As the network grows, it will be a key defense mechanism against bioterrorism worldwide, improving protection measures to citizens worldwide.