A catastrophic health event, such as a terrorist attack with a biological agent, a naturally occurring pandemic, or a calamitous meteorological or geological event, could cause tens or hundreds of thousands of casualties, weaken the economy, damage public morale and confidence, create panic and civil unrest, and threaten national security. It is therefore critical to establish a strategic vision that will enable a level of public health and medical preparedness sufficient to address a range of possible disasters. Planning for a catastrophe involving a disease outbreak or mass casualties is an ongoing challenge for first responders and emergency managers. They must make critical decisions on treatment distribution points, staffing levels, impacted populations, and potential impact in a compressed window of time when seconds could mean life or death. Some of the key areas of public health and medical preparedness include medical surge, population protection, communication infrastructure, and emergency evacuation. This article highlights our own experience on projects with the Centers for Disease Control and Prevention and various public health jurisdictions in emergency response and medical preparedness for mass dispensing for disease prevention and treatment, and large‐scale disaster relief efforts.