4 October

Western Front

 * Rapid German advance towards the Coast: Germans occupy Lens, Comines, Poperinghe, Bailleul, etc.
 * Lille bombarded by Germans.

Eastern Front

 * Poland: Rapid Austro-German advance against Russian centre.

Southern Front

 * Bosnia: Serbians and Montenegrins driven back from the Sarajevo region.

Political

 * German Professors' manifesto issued.