The events of September 11, 2001, presented a statistical challenge to the National Center for Health Statistics (NCHS) on how to characterize and classify, report, and analyze deaths and injuries associated with terrorist events. The definition of terrorism, addressed by an ad hoc work group, was “the unlawful use of force or violence against persons or property to intimidate or coerce a Government, the civilian population, or any segment thereof, in furtherance of political or social objectives.” To classify a death as terrorist related, it is necessary for the incident to be designated as such by the Federal Government. The primary limitation for classifying a death to homicide due to terrorism or suicide due to terrorism is the failure of the incident to be labeled as such. If there is a delay in determining that an incident was a result of terrorism, this could create a possible delay for classifying deaths to their ultimate International Classification of Diseases (ICD) code. Another limitation is that deaths may not be assigned to more specific categories than “homicide, terrorism” because of limited information on the death certificate. The terrorism codes are designed to fit within the framework of the classifications presently used for mortality --the ICD-10 for mortality. Separately identifying codes for terrorism as subcategories of homicide and suicide will allow the United States to document the number of such deaths for any given period or geographic locale. These codes do not replace codes for “Operations of War” or deaths resulting from a declared state of war. State vital statistics offices were informed of the new codes during the spring of 2002 for immediate implementation. New mortality codes would begin with deaths on September 11, 2001. Because identification and tracking of terrorism are in the Federal Bureau of Investigation’s domain, this new set of codes is not intended to be a refined classification encompassing all aspects of terrorism. 1 table, 7 references