We describe the cloning, expression pattern, and genomic organization of Lbx2, a murine homologue of the Drosophila and mammalian ladybird genes. Lbx2 includes a homeodomain motif most closely related to those of Lbx1 and the Drosophila ladybird proteins. Lbx2 transcripts are first detected at E10.5 when they are located in the gonadal component of the urogenital ridge. Expression of Lbx2 dramatically increases by E11.5 in the urogenital ridges, and in the cranial surface ectoderm. At later stages, Lbx2 transcripts are expressed in the brain and organs derived from the urogenital ridge, including the gonadal tubercle, kidneys, and adrenal glands. From E14.5 to birth, Lbx2 expression is evident in the developing retinal neuroepithelium and the vibrissa.