26th Army was a part of the Southwestern Front and defended the Soviet-German border between Przemyśl and the Carpathian Mountains in June 1941.

The Army was located on the eastern bank of San river manning the 8th Fortified District.

On 23 June General Kirponos ordered 26th Army armour troops (8th Mechanized Corps) to move to Brody out of the command of Kostenko.

The 26th Army was quickly rebuilt in October 1941 by subsequent reinforcements and included elements of the 1st Guards Special Rifle Corps and now defended the Dnieper river at Kaniev and Rzhishchev south-west of Kiev.

Commander: Lieutenant General Grigory Grigorievich Sokolov (November–December 1941) The army was reformed for the fourth time within the Karelian Front in March–April 1942.

[12] On 1 January 1943 the army comprised 27th, 54th, 186th, and 263rd Rifle Divisions, 61st, 67th, 80th (less 2nd Battalion), and 85th Naval Infantry Brigades, artillery, and other units.