Résumé : The screening of a bovine genomic library with a human tumour necrosis factor-αTNF-α) cDNA probe resulted in the isolation of a 7.2 kb DNA fragment containing the entire bovine TNF-α gene. Analysis of this genomic clone showed that it also contains the bovine lymphotoxin (LT, TNF-β) gene. Comparison to published sequences of human, murine, ovine nd rabbit counterparts allowed us to delineate the coding sequences, the promoters and the enhancers of these two genes. Sequences involved in the regulation of translation and in the mRNa stability were found in the 3′ untranslated regions. © 1993.