The present study aims at proving that the novels of Don DeLillo (1936) belong to the genre of hysterical realism. In White Noise (1985) and Cosmopolis (2003), DeLillo highlights the repercussions of modernist materialism and postmodernist approval of uncertainty, representation over reality and chaos in the American society, and which eventually lead to diminish the spiritual aspect of religion, and magnify materialistic values represented by scientific, technological and medical advances. Hysterical realism in White Noise and Cosmopolis is mainly incarnated in the characters' desperate and absurd attempts to escape their fear of death and to adhere to the mundane life. The study critically tackles the characteristics of hysterical realism, and the common features in the two novels. Two important findings of the study are: DeLillo's severe criticism of the chaotic skeptic world created by embracing postmodern ideals through the conventions of realism but in an absurd way; and DeLillo's implied invitation for the Americans to revive the role of religion in their life, so as to act as a spiritual remedy for the evils caused by the modernist/postmodern principles