Through an examination of Luís Buñuel's 1933 documentary Las Hurdes, this essay engages and expands on the notion of indexical realism. The film signals Buñuel's distancing from orthodox surrealism in favor of a politically complex examination of the region of Las Hurdes as a national and ethnographical commonplace. The argument hinges on Buñuel's use of the absolute and impossible perspective of the hurdanos. Through his use of an eschatological avant-gardism, he catches a glimpse of the Real, as a radical expression of exteriority. Las Hurdes emerges as a paradigmatic example of a revolutionary form of ontological cinema that contains a theory of non-mimetic referentiality. Indexical realism refers here to an understanding of realism that is not concerned with representation or mimesis but with the ability to point deictically, as an index, to a reality that is necessarily outside the realm of representation. Thus the target of Buñuel's indexical realism is not representation but presence. Representation is only its byproduct, which often takes the form of an interruption of presence. Indexical realism hints at the exteriority of presence through discontinuities and ruptures of semblance. Politically, Las Hurdes emerges from this discussion as an expression of fidelity to the radical otherness of the hurdano event, the exteriority of their death, which in turn becomes the index that validates the film as a political gesture. Buñuel's indexical realism thus stands as an ethical and aesthetic counterpart to the restrained political action that would occupy Spanish intellectuals during the 1930s.