The albumin gene family consists of four evolutionarily related genes that code for serum transport proteins. In rodents, the genes for albumin, alpha-fetoprotein, and alpha ALB are physically linked within 100 kilobases of DNA. The fourth gene, Gc, encoding vitamin D-binding protein or group-specific component, maps to the same chromosome as the other family members, but linkage has not been established. This report describes the genetic and physical mapping of Gc in mouse and establishes that, although Gc is genetically linked to the other genes, its physical distance from them extends beyond the resolution range of yeast artificial chromosome cloning and pulsed-field gel electrophoresis.