Tumor necrosis factor-alpha (TNF-α), produced by immune cells, is a cytokine with a central role in the mediation of inflammatory responses to infection and injury. We report the nucleotide and corresponding amino acid sequence of a full length porcine TNF-α cDNA. The complete cDNA nucleotide sequence is 1650 bp in length (not including the poly A tail) and has an open reading frame of 696 bp encoding a 232 amino acid protein. The porcine TNF cDNA sequence shows homologies of 86, 77, and 82% to human, murine, and lapine TNF cDNA sequences in the coding regions, respectively. The 5’ untranslated region of the cDNAs shows little sequence similarity. However, the 3’ untranslated region contains highly conserved sequences among all species, especially the TTATTTAT motif characteristic of cytokine messages.