The events of September 11, 2001, the subsequent anthrax attacks that followed, and the aftermath of Hurricane Katrina demonstrated that there were clear weaknesses in public health's ability to respond in an emergency. The Center for Infectious Diseases &Emergency Readiness, a CDC-funded Center for Public Health Preparedness, is applying to become a CDC Preparedness and Emergency Response Research Center (PERRC). The mission of the Center is to conduct public health research that improves the capability of public health departments and communities to prevent, detect, investigate, and respond to public health threats from all hazards. In achieving our mission, we will serve effectively our most vulnerable populations. With the theme to Create and Maintain Sustainable Preparedness and Response Systems, we will focus on the following public health systems research areas: (1) all-hazards communication to improve the resilience of vulnerable populations;(2) early warning, investigation, and surveillance: epidemiology networks in action;(3) closing the chemical, biological, radiological, and nuclear gaps in public health all-hazards preparedness;(4) optimizing public health emergency management systems;and (5) California Exercise Laboratory: systems research using statewide operations-based exercises. We have assembled a multi-institutional, interdisciplinary all-hazards research team involving: the University of California at Berkeley, School of Public Health;Louisiana State University, School of Business &the Stephenson Disaster Management Institute;Monterey Institute of International Studies, James Martin Center for Nonproliferation Studies (specializing in terrorist threats from chemical, biological, radiological, and nuclear weapons);State of California (California Department of Health, Governor's Office of Homeland Security, and Emergency Medical Services Authority);State of Hawai'i Department of Health, Division of Disease Control;and the University of Pittsburgh Graduate School of Public Health PERRC. As a center in an academic institution, our tradition of partnering with local and state health departments will enable us to tackle the challenges of studying public health systems in order to strengthen all-hazards public health emergency response nationally.