Organisation (November 1941): 86th, 129th and 162nd Infantry Divisions; Gruppe Landgraf (parts of 6th and 7th Panzer Divisions) The XXVII Corps did not take part in the initial stages of Operation Barbarossa, but was transferred to the Ninth Army, Army Group Centre, for Operation Typhoon, the attack on Moscow.

Organisation (July 1943): 52nd, 197th, 246th and 256th Infantry Divisions In the autumn of 1943 the Corps, now assigned to Fourth Army, took part in the defence against the Soviet offensive Operation Suvorov around Smolensk.

In late June the Soviets commenced their summer offensive, Operation Bagration; the XXVII Corps was attacked by forces of the 3rd Belorussian Front and took heavy casualties.

Bypassed by a breakthrough of Soviet forces to the north, the Corps found itself encircled in the forests east of Minsk, and despite a breakout attempt on 5 July spearheaded by the 25th Panzergrenadier Division, was almost entirely destroyed.

The Corps, and its staff, was hurriedly reconstructed in July / August from replacement units and deployed on the East Prussian border.