Lhx8 is a LIM-homeodomain protein, containing two tandemly repeated LIM motifs and a hemeodomain. The expression of Lhx8 is limited spatially to the medical ganglionic eminence and the mesenchyme surrounding the oral cavity and temporally from middle embryonic to early postnatal development, suggesting a role for Lhx8 in differentiation of certain neurons and mesenchymal cells, just as the other LIM-homeodomain proteins are implicated in determining the fates of certain cell types. Here we report the structure and the chromosomal localization of the Lhx8 gene. The gene is composed of nine exons and eight introns. The first LIM domain is coded by two exons, exons 2 and 3, and the second by a single exon, exon 4. The homeodomain is encoded by three exons, exons 6, 7, and 8. In situ chromosomal hybridization demonstrated that the Lhx8 gene was localized in the distal region of mouse chromosome 3.