Abstract: cDNA was synthesized using the whole RNAs extracted from bovine omasal flakes in the present study. The cDNA of bovine type Ⅰ small peptide transporter (BPepT1) was amplified by RT-PCR using primers designed according to the published sequences of human, mouse, rabbit, and sheep PepT1 in GenBank. The amplified segment was sequenced after purifying and cloning. After comparing with the published PepT1 sequences of other animals, the 1 566 bp sequenced segment (DQ309694) was a sequence encoding the peptide chain from 3rd to 10th transmembrane structural domains of BPepT1. Homologous analysis indicated that the sequenced segments of BPepT1 had 82.89%, 80.14%, 78.93%, 96.04%, 83.08%, 63.90%, 85.66% nucleotide identity and 81.45%, 79.62%, 76.25%, 94.06%, 81.49%, 61.41%, 83.56% amino acid identity with the corresponding segments of human, rat, rabbit, sheep, dog, chicken, and pig PepT1, respectively. Comparison of the PepT1 amino acid sequences encoded by the sequenced segments of eight animal species (bovine, human, mouse, rabbit, sheep, dog, chick, and pig) indicated that PepT1 was a highly conservative protein during evolution, and the amino acid sequences in the transmembrane structural domains were more conservative than those in the outside domain sequences. The amino acid identities of the 12 structural domains were all above 90%, and the identities from 3rd to 10th domains were 90.97%, 91.07%, 97.62%, 93.45%, 94.05%, 91.67%, 91.45%, and 95.83%, respectively. The amino acid identities of the outside domain regions ranged from 70% to 99%, and the amino acid identities of the 3-4, 4-5, 5-6, 6-7, 7-8, 8-9, and 9-10 outside-domain regions were 77.63%, 98.86%, 86.72%, 90.13%, 91.25%, 88.33%, and 71.74%, respectively. The outside domain region between the 9-10 trans-membrane domains is a big extracellular loop, which may be an important structure in substrate recognition by PepT1. The amino acid identity in the region between bovine and chick was quite and only 29.3%, but the amino acid identities between bovine and mouse, dog, human, rabbit, pig, or sheep were 65.17%, 71.64%, 67.16%, 60.20%, 73.13%, and 88.56%, respectively. Predicated from the published consensus amino acid sequences, there were six N-linked glycosylation sites, three cAMP-dependent protein kinase (PKA) sites, and one protein kinase C (PKC) site in the amino acid sequence encoded by the sequenced segment of BPepT1.