In the United States, the national policy for foot and mouth disease (FMD) vaccination lacks clarity. To better understand what potential Incident Commanders see as important 'triggers' or factors to consider for implementing vaccination as a control strategy, the authors presented seven such individuals with an FMD outbreak scenario that started in north-western Illinois and spread across state lines by the end of the fifth week. The scenario had four infected premises at the end of week one, 13 at the end of week two, and 60 (including both infected and previously depopulated premises) by the end of week five. Two individuals favoured vaccination the first week of the outbreak scenario, one did not want to vaccinate during the scenario, and the remainder wanted vaccination at some time during the scenario. Respondents ranked nine specific factors to take into consideration when deciding whether or not to vaccinate. Of these, the capability to manage the outbreak by stamping out ranked first. Many of the issues raised in this report are applicable to other countries that are currently FMD-free without vaccination.