This paper presents the development of mining extraction of tungsten in western Spain during the First World War, more particularly in Galicia, Castile and Leon, Extremadura and Andalusia. Its extraordinary development happens by the unquestionable technological advances that allowed its use for military purposes of maximum value. So much so, that the two sides in the war spent a significant part of their war effort to obtain it. The mining extraction will increase especially in the years 1916, 1917 and 1918, with many activities nothing lawful. At the conclusion of the war, this metal was practically forgotten until the Second World War.