The homotrimeric Fas receptor, an inducer of lymphocyte apoptosis, plays a critical role in cellular pathways of immune homeostasis and immunologic tolerance. Inherited and acquired defects in the Fas gene, TNFRSF6 (tumor necrosis factor receptor superfamily member 6) have been associated with human autoimmune lymphoproliferative syndrome (ALPS) and a spectrum of other complex autoimmune diseases and malignancies. In addition to over 60 deleterious mutations associated with dominant inhibitory defects or null mutations of TNFRSF6, several sequence variants have been noted. To facilitate interpretation of genotypes of this important locus, we sequenced DNA from unrelated, healthy Caucasians and African Americans. Two new and 12 previously recorded SNPs were confirmed, and their allele frequencies were determined. We also investigated haplotype frequencies and linkage disequilibrium (LD) coefficients for these SNPs in Caucasians. Four TNFRSF6 SNP pairs were found to be in strong LD. The TNRFSF6 SNPs are useful for linkage and loss of heterozygosity studies probing the role of Fas-mediated apoptosis in autoimmune diseases and malignancies.