The key aim of this article is to expose the specificity of the theory of totalitarianism in the context of Cardinal Wyszyński’s humanitarian-personalist concept of socio-political life. Hence, it provides a unique insight into the nature of totalitarian systems, both German Nazi Hitlerism and Communism. Analyses were performed to reinterpret the above systems from the perspective of Christian personalist praxeology, taking into account the fundamental assumptions of the absolutely anti-human and anti-Christian paradigm that not only defined but also legitimized and even authenticated the most terrible and degenerated forms of totalitarian systems of the 20th century. Therefore, it is crucial, especially today, when emerging tendencies often trivialize the criminal nature of that systems and even treat the “totalitarian model” – particularly in the context of Communism – as a “specific historical phenomenon” aimed at resolving many complicated socio-political, cultural, and economic issues.