The mouse UGRP gene family consists of two genes, <i>Ugrp1 </i>and <i>Ugrp2</i>. In this study, the genomic structure and expression patterns of <i>Ugrp2</i> and its alternative spliced form were characterized. The authentic <i>Ugrp2 </i>gene has three exons and two introns, similar to the <i>Ugrp1</i> gene, which produces a secreted protein. The <i>Ugrp2</i> variant uses a sequence located between authentic exons 1 and 2, resulting in a cytoplasmic form due to a termination codon within the inserted sequence. Both mouse and human UGRP2 mRNAs are expressed in lung. In the case of human, the mRNA is expressed at the highest level in trachea, followed by salivary gland at a level similar to lung. Weak expression was also found in fetal lung and mammary gland. <i>Ugrp2 </i>was mapped by fluorescence in situ hybridization to mouse chromosome 11A5–B1 and human chromosome 5q35. These regions are known to be homologous. Interspecific mouse backcross mapping was also performed to obtain further detailed localization of mouse <i>Ugrp1</i> and <i>Ugrp2</i>.