ISSUE: Intentional and unintentional mass-casualty incidents, (MCIs), including epidemics, weather-related events, and mass trauma are likely to cross city, county, and even state lines. Significant MCIs in one community may impact multiple disciplines and multiple agencies. Hospitals should collaborate with other partners in the planning for, response to, and recovery from any incident. PROJECT: This abstract describes the development of a healthcare coalition for emergency preparedness in Idaho. In early 2001, a team of hospital managers and disaster coordinators developed a regional response matrix that included emergency notification contacts at each facility, resource management, and communication needs. In 2002, the Healthcare Coaliton for Emergency Preparedness (HCEP) expanded to include regional responders in 14 counties and one bordering state, including fire, emegency medical services, county disaster coordinatiors, public health, law enforcement, Civil Support Team, regional hazardous materials (HazMat) response teams, and hospital infection control practitioners. The coalition membership also includes the United States Health Resources and Services Administration Bioterrorism Preparedness Program. RESULTS: An assessment of response capability was completed and draft memoranda of agreement were developed for communication and resource sharing. The coalition developed and approved a charter, mission statement, and membership. An emergency conference call process was developed and has been used for HazMat incidents, suspicious packages and threat events, and urgent communication needs. A regional infectious disease emegency response plan was developed. This plan was activated in 2004 due to the shortage of influenza vaccine. Regional exercises have been conducted, including specific coalition action items. LESSONS LEARNED: A healthcare coalition for emergency preparedness that includes first responders, hospitals, and other partners is essential for effective emergency response. An integrated emergency response plan can minimize the impact of an incident in the field and at the hospitals, whether it be an MCI event, HazMat Event, or Infectious Disease Event.