The complete sequence of caprine β-lactoglobulin cDNA has been determined. The caprine β-lactoglobulin cDNA consists of 540 nucleotide coding region, flanked by 40 nucleotide 5`-untranslated region (UTR) and 207 nucleotide 3`-UTR which was followed by 78 nucleotide polyadenylation. The coding region encodes 180 amino acids which consist of l8 amino acid-long signal peptide and 162 amino acid-long mature β-lactoglobulin. The caprine β-lactoglobulin cDNA differs from that of its ovine counterpart by 7 nucleotides in the protein coding sequence resulting in 2 amino acid changes at amino acid positions -3 and +130. The nucleotide sequence at 5` -UTR and coding region was highly conserved with respect to the ovine β-lactoglobulin and was more homologous to ovine cDNA (99%) than the bovine cDNA (94%). However, the 3` -UTR of the caprine β-lactoglobulin mRNA was less conserved and it is more homologous to bovine cDNA (94%) than that of the ovine mRNA (90%). The sequence analysis revealed that the β-lactoglobulin molecules are highly conserved during the evolution of ruminant species.