This article discusses the 1940 "International Surrealist Exhibition," a paradigmatic event in the history of Surrealism's transition between Old and New Worlds. Breton’s brainchild, the show claimed a large part of Mexico's national art canon as part of the transnational Surrealist cause. Proving controversial in a heavily nationalist art scene, the show continues to occupy a conflicted position in the historiography of Mexican art. Many describe it as the pivotal event that drove art in Mexico away from nationalism, while others trivialize its impact. In the 1969 book El Surrealismo y el Arte Fantástico de México, the most ambitious response to the 1940 show ever produced, art historian Ida Rodríguez-Prampolini takes the latter position. Much of what Breton and his circle viewed as surrealist in Mexican art, Rodríguez argues, was instead part of the country’s own “fantastic” tradition, in place long before Surrealism arrived. A chauvinist treatise on Mexican identity at first glance, this essay argues that the book instead is emblematic of a long history of anxious relationships between definitions of national identity and the practice of art history in post-revolutionary Mexico.