The murine beta-glucuronidase structural gene (Gus-s) has been isolated from a BALB/cJ sperm DNA bacteriophage library and its nucleotide sequence established. The gene is organized into 12 exons comprising 17.5% of the 14,009 base pair (bp) region spanning the interval between transcription initiation and the putative site of polyadenylation. A TATA box sequence, embedded within a GC-rich region, is found 28 bp upstream from the transcription initiation site. Eleven members of the B1 family and eight members of the B2 family of murine repetitive elements were identified within Gus-s and 2440 bp of flanking sequence. Other novel sequences found within Gus-s, including a (AC)19 homocopolymer tract within intron 3 and a 23 base pair complex direct repeat within intron 9, are presented and discussed.