We have recently shown that the Ca2+ dependent cell adhesion molecule uvomorulin is encoded by a single gene, localized on mouse chromosome 8. Here we describe the organization of the uvomorulin gene and give an initial characterization of the uvomorulin promoter. Uvomorulin is encoded by 16 exons, which are distributed over a region of more than 40 kb genomic DNA. The exon structure of the genes for uvomorulin and its chicken homologue L-CAM are nearly identical and thus highly conserved. The relationship between the exon structure and the structure of the uvomorulin protein is analysed. The initiation site of transcription of the uvomorulin gene is located 127 bp upstream of the translation start site in a GC-rich region with no TATA-box, but with a GC-box in position -48 and a CCAAT-box starting at position -65 with respect to the transcription start site. 1.6 kb of the uvomorulin promoter (-1492 to + 92) confer cell type specific promoter activity to the CAT reporter gene. Homologies to known cis acting elements of other promoters are discussed.