Following Soviet counterattack to the Polish Kiev Offensive, the Regiment began to retreat westwards. By June 19, it defended the line of the Sluch River, with heavy losses, which shrank its manpower. In late July 1920, the Regiment was sent to Tarnow, to recuperate and increase its refill its ranks with new recruits. On July 22, the unit came to Zamość, joining the forces of General Juliusz Rómmel. Until August 8 it fought along the Styr River, but due to numerical superiority of the enemy, it was forced to retreat to Radziechów. Pushed by the enemy, the Regiment crossed the Bug River, entering Żółkiew. There, it attacked a wing of the Budionnyi army. On August 29, the Regiment captured Tyszowce, and then fought the Soviets near Zamość, in the famous Battle of Komarów.