In spite of great advances in medicine, serious communicable diseases are a significant threat. Hospitals must be prepared to deal with patients who are infected with pathogens introduced by a bioterrorist act (e.g., smallpox), by a global emerging infectious disease (e.g., avian influenza, viral hemorrhagic fevers), or by a laboratory accident. One approach to hazardous infectious diseases in the hospital setting is a biocontainment patient care unit (BPCU). This article represents the consensus recommendations from a conference of civilian and military professionals involved in the various aspects of BPCUs. The role of these units in overall U.S. preparedness efforts is discussed. Technical issues, including medical care issues (e.g., diagnostic services, unit access); infection control issues (e.g., disinfection, personal protective equipment); facility design, structure, and construction features; and psychosocial and ethical issues, are summarized and addressed in detail in an appendix. The consensus recommendations are presented to standardize the planning, design, construction, and operation of BPCUs as one element of the U.S. preparedness effort.