Recently, a 500-kDa protein, with homology to the rat Gp330 glycoprotein, was found to be expressed on the surface of human parathyroid, placental cytotrophoblast, and renal proximal tubule cells. The protein has been implicated to function as a sensor of extracellular calcium on parathyroid and placental cytotrophoblast cells. We report here in situ hybridization mapping of the corresponding gene, designed as low-density lipoprotein receptor related protein-2 and symbolized as LRP2, to human chromosome region 2q31-->q32.1 and porcine chromosome region 15q22-->q24. The results are discussed in a comparative mapping context.