This work presents the eastern front of the Second World War, where the Third Reich and the USSR clashed. Two large and industrially strong states that often cooperated together. At the head of the USSR is a communist dictatorship, while in the Reich it is a Nazi one. Two opposing ideologies engage in a conflict that is the bloodiest of the entire war and claims more lives than any other front. The aim of the paper is to determine whether and to what extent ideologies created such a large number of victims. In order to make it clearer what is being said, the ideologies are explained and their relationships established. After the establishment of these two points, the components of the two ideologies were studied, from the way they treat the family unit to the military organization, and whether there is an influence of ideology on these points. The repressive apparatus of both states was also studied. The repressive apparatus consists of secret police and concentration camps. The secret police send the unfit to these camps, who are then killed or forced to do hard labor. Organized murders and atrocities such as the massacre in Babi Yar or in the Katyn Forest were studied to establish ideological connection to these crimes and whether there was an ideological plan that called for such murders. At the end, the conclusion about the whole work was established and the question was answered whether the number of victims would be lower if the mentioned ideologies were not at the head of their countries.