A Machine Gun Company, of the Canadian Machine Gun Corps, was attached to each Canadian Infantry Brigade, until the formation of Canadian MG Battalions.
The 3rd C.M.G. Coy. was attached to the 3rd Infantry Brigade, 1st Canadian Infantry Division.
It was mobilized on 01 January, 1916 near Meteran; although was unable to obtain guns for several months. It was formed from the MG Sections of the Infantry Battalions of the Brigade.
On 27 March, 1918, it was amalgamated with the 2nd C.M.G. Company to form No. 1 Company, 1st Bn, C.M.G.C..