The structure and organization of the human vitamin D-binding protein (DBP) gene has been determined. The gene is composed of 13 exons and 12 intervening sequences. With the help of the polymerase chain reaction (PCR) introns were amplified using exon-specific oligonucleotide primers, and were sequenced after subcloning; the exon/intron borders were determined. The introns 2, 5, 7, 9 and 10 were sequenced completely; the introns 1, 3, 4, 6, 8, 11 and 12 were sequenced in part. We designed intron-specific primers for the amplification of each exon by the PCR-method. This permits the analysis of mutational and function-related sites. By comparison with the genes for human albumin and alpha-fetoprotein the gene for DBP/GC is confirmed as a member of this multigene family. The location of the introns in the coding region of the human DBP-gene is identical with the position of the introns in the rat DBP-gene.