The complete cDNA sequence of the major epidermal growth factor binding protein (EGF-BP), isolated from the mouse submandibular gland, has been determined. Oligonucleotide probes complementary to unique, nonconserved, regions of homogeneous preparations of EGF-BP were used to identify the correct cDNA clone from a male mouse submandibular gland cDNA library. The nucleotide sequence codes for a glandular kallikrein that is the main arginine esterase complexed with epidermal growth factor. The mRNA coding for this EGF-BP is estimated at 0.24% of the total mRNA of the adult male mouse submandibular gland, thus representing an abundant member of the kallikrein family in this tissue. In addition, the cDNA sequence defines a putative transcription start site. The reported cDNA sequence is clearly different from, and not an allelic form of, a previously reported cDNA sequence for EGF-BP. The present work reconciles conflicting information in the literature regarding the identity of EGF-BP.