The article analyses transatlantic relations through the prism of civilisational difference. First, it suggests that the character of the current tensions between the United States and some European countries is primarily civilisational, and only secondarily political, diplomatic, military or economic. It is in this context that the central thesis of the civilisational difference is presented. This difference, it is claimed, springs from the dissimilar relation of the substantial part of Europe and that of America toward the classical and the Christian Great Tradition. The difference is then exemplified by the intersection of politics and economic life as well as the broadly understood issues of church and state, with special emphasis on the concepts of faith, reason, and freedom. The central part of the article analyses the very essence of the civilisational difference, juxtaposing American social and juridical dualism/pluralism and European monism. The difference is presented as the result of the essential continuity between the American tradition and the pre-modern heritage of the West on the one hand and the break with this heritage in the case of the absolutist and post-Enlightenment European tradition on the other. Finally, the article attempts to show how the category of civilisational difference may throw some new light upon current, difficult transatlantic relations. This is done, among other things, by the comparative analysis of selected excerpts from two famous declarations written by European and American intellectuals after September 11th, 2001.