Significance The lack of viable tumor-specific targets continues to thwart efforts to implement selective anticancer drugs in the clinic. Clonal loss of heterozygosity (LOH) occurs in the great majority of human tumors and represents an irreversible genetic alteration present in cancer cells that unequivocally distinguishes them from normal cells. Here, we report the development of NASCAR (Neoplasm-targeting Allele-Sensing CAR), a platform comprising pairwise chimeric receptors for detecting and targeting LOH events in cancer. As proof-of-concept, we demonstrate specific NASCAR T cell responses in models of HLA LOH in vitro and in vivo. This work lays the foundation for future exploration and exploitation of LOH-mediated vulnerabilities for precision cellular immunotherapy.