The Department of National Defence , commonly abbreviated as DND, is a Canadian government department responsible for defending Canada's interests and values at home and abroad. National Defence is the largest department of the Government of Canada in terms of budget as well as staff. It also is the department with the largest number of buildings (6,806 in 2015). The Department is headed by the Deputy Minister of National Defence, who is the Department’s senior civil servant, and reports directly to the Minister of National Defence.