The aim of this article is to analyse the effects on Spain as a neutral country of the monetary measures adopted by the largest allied nations during the First World War. We will focus on the intervention of exchange rates and on the measures aimed at limiting gold outflows from belligerent countries. The distortions derived from these policies gave rise, in some cases, to additional profits for Spanish exporters and intermediaries, while in others prevented the effective transformation of some benefits from war into valuable assets and pushed them to be dragged down by the economic disturbances of the post-war period.