The complete mitochondrial genome sequence of the pig, Sus scrofa, was determined. The length of the sequence presented is 16,679 nucleotides. This figure is not absolute, however, due to pronounced heteroplasmy caused by variable numbers of the motif GTACACGTGC in the control region of different molecules. A phylogenetic study was performed on the concatenated amino acid and nucleotide sequences of 12 protein-coding genes of the mitochondrial genome. The analysis identified the pig (Suiformes) as a sister group of a cow/whale clade, making Artiodactyla paraphyletic. The split between pig and cow/whale was molecularly dated at 65 million years before present.