Map showing the Polish assault southwards
Battle of Bzura
Conflict	Polish Defence War of 1939
Date	September 9 to September 18, 1939
Place	along the shores of Bzura River near Kutno
Result	German victory
Combatants Poland Germany Commanders Tadeusz Kutrzeba Władysław Bortnowski Gerd von Rundstedt Johannes von Blaskowitz Strength 8 infantry divisions, 2 cavalry brigades 12 infantry divisions, 5 armoured and motorised divisions Casualties unknown unknown
Polish Defence War of 1939 Westerplatte - Krojanty - Mława - Mokra - Gdańsk Bay - Mikołów - Pszczyna - Węgierska Górka - Jordanów - Tuchola Forest - Łódź - Borowa Góra - Piotrków - Tomaszów - Różan - Radom - Łomża - Wola Cyrusowa - Hel - Wizna - Gdynia - Iłża - Warsaw - Bzura - Jarosław - Modlin - Kałuszyn - Węgrów - Lwów - Kobryń - Brześć - Kępa Oksywska - Tomaszów Lubelski - Kampinos Forest - Janów Lubelski, Wereszyca and Hołosko - Krasnystaw - Grodno - Cześniki - Krasnobród - Władypol - Szack - Wytyczno - Parczew - Kock

Battle of Bzura (also known as Battle of Kutno) took place during the Second World War, Polish September Campaign between 9 September, 1939 and 18 September, 1939 and was fought between Polish and German Nazi forces.

It was the largest battle during this campaign. It took place near the Bzura river west of Warsaw. It was the Polish attempt at a counterattack, which failed after an initial success.

Polish forces consisted of Armies 'Poznań' and 'Pomorze'. German forces consisted of Armies 8 and 10 from Army Group Sud.

The battle can be divided into 3 phases:

• Phase I - Polish offensive on Stryków (9-12 September)
• Phase II - Polish offensive on Łowicz (13-16 September)
• Phase III - Polish retreat towards Warsaw and defeat

pl:Bitwa nad Bzurą