On 26 August 1939, details of the 17th Duke of York's Royal Canadian Hussars were called out on service and then on 1 September 1939, placed on active service under the designation as the 17th Duke of York's Royal Canadian Hussars, CASF, for local protection duties. With the outbreak of WWII, the 17th Hussars became the last Canadian cavalry regiment to pay off their horses and become mechanized. On 31 December 1940, those details called out on active service were disbanded.
