Using a prostate-specific antigen cDNA as a hybridization probe, clones containing the kallikrein genes encoding prostate-specific antigen, human glandular kallikrein-1 and pancreas/kidney kallikrein were isolated from a human genomic library. Clones containing the prostate-specific antigen gene and the human glandular kallikrein-1 gene overlap and span a region of about 36 kb. The two genes are aligned in a head to tail orientation at a mutual distance of 12 kb. Southern blot analysis of DNA from a panel of human-hamster hybrid cells with specific probes revealed the genes to be situated on chromosome 19. Assuming that the pancreas/kidney kallikrein gene is located in the same cluster, the distance to the prostate-specific antigen gene and the human glandular kallikrein gene must be at least 15 kb.