In March it took part in the suppression of rebellions in the Stavropol, Melekessk and Syzransk counties, and then moved to Lbichensk, Slymhinskaya, Oral and Guriev to fight against the Spring Offensive of the Russian Army (1919).
The offensive of the 4th Army of the Western Front began on July 2, 1920, near the Latvian border in the city of Dzisna.
In five weeks time, the Army advanced more than 800 kilometers, occupying a significant part of the territories of Belarus and Poland, including: Święcany, Vilnius, Grodno, Mława, Ciechanów, etc.
On August 17, 1920, the day before the planned beginning of the decisive Soviet offensive on the Vistula, Pilsudski's army undertook a powerful counteroffensive.
The 4th Army and the 3rd Cavalry Corps almost ceased to exist as fighting units as many soldiers were forced to flee into German territory, where they were interned.
From September 14, 1920, replenished with fresh divisions, the 4th Army again participated in heavy fighting in Belarus, including the Battle of Kobryń (1920), after which it retreated to the Slutsk area.