The Fas antigen is a receptor protein transducing cell death signals. Binding of Fas ligands to Fas antigens provokes apoptosis in target cells. Here we report the structure of the promoter of the gene coding for rat Fas antigens. The major transcription start site, identified by the S1 nuclease protection assay, was situated 188 nucleotides upstream of the translational initiation site. The promoter activity was located in the region at the nucleotide position from -142 to -24. In this region we identified a consecutive sequence of NF-kappaB and NF-IL6 consensus sequences, spanning from -142 to -122.