The Chemical and Biological Defense Division (CBD) is a division of the Science and Technology Directorate of the United States Department of Homeland Security. Within the Homeland Security Advanced Research Projects Agency, CBD develops technologies to increase the United States's preparedness and protect key national infrastructure against chemical, biological, and agricultural threats and disasters through improved threat awareness and advanced surveillance, detection, and protective countermeasures.

The 2007 High Priority Technical Needs brochure published by Homeland Security defines critical focus areas for chemical and biological research, falling primarily under the category of "chemical/biological weapons defense":

 This article incorporates public domain material from websites or documents of the United States Department of Homeland Security.