This article recalls the chief points of the personalist philosophy of Dietrich von Hildebrand and his opposition to the foundations of the national-socialist ideology. His struggle was waged against relativism and positivism, from which arose national-socialism, which he considered radically anti-christian. He defended an authentic personalism, which was based on the primacy of the spiritual dimension in relation to the vital dimension. Von Hildebrand strove against the ideological roots of racism and anti-semitism, and also against collectivism and the totalitarianism of the state and of the party.