The 45th Reserve Division fought on the Western Front, entering the line in October along the Yser and remaining there until April 1915, when it went into the fight for Ypres. The division remained in the Yser region until September 1916. In September, the division fought in the Battle of the Somme. Thereafter, it remained in the Aisne region until April 1917. In April and May 1917, it fought in the Second Battle of the Aisne, also known as the Third Battle of Champagne (and to the Germans as the Double Battle on the Aisne and in the Champagne). Thereafter, the division went into the trenchline around Verdun, remaining there until the end of September 1917, when it joined the Battle of Passchendaele. The division then returned to Verdun. In 1918, it fought in the German spring offensive, including the breakthrough at St. Quentin and the follow-on battles in the Montdidier-Noyon region. It later saw action in the Second Battle of the Marne and the Meuse-Argonne Offensive. In 1918, Allied intelligence rated the division as second class.