The mouse counterpart of the human inter-alpha-trypsin inhibitor family heavy chain-related protein (IHRP), inter-alpha-trypsin inhibitor family heavy chain-related protein, was partially purified from mouse serum through Western blot analysis using anti-human IHRP antibody. The amino-terminal amino acid sequence was then determined, and the cDNA clone encoding mouse IHRP was isolated and characterized. The mouse IHRP amino-terminal amino acid sequence matched the predicted sequence from the cDNA, and has high homology compared with human and pig IHRP. Furthermore, the whole mouse IHRP amino acid sequence predicted from the cDNA nucleotide sequence showed reasonable homology to that of both human and pig IHRP. Mouse IHRP expression was induced by treatment with typical inflammation-inducing compounds, such as turpentine and lipopolysaccharide.