We mapped the proteins of human urine by high-resolution two-dimensional electrophoresis, utilizing the ISO-DALT system. Wide-range pH gradients and narrow-range acid gradients were both used in the first-dimension separations. The patterns revealed proteins ranging in relative molecular mass from 10 000 to 90 000. Proteins identified in the map included transferrin, albumin, hemopexin, alpha 2-HS glycoprotein, alpha 1-antitrypsin. Gc globulin, alpha 1-acid glycoprotein, Zn alpha 2-glycoprotein, retinol binding protein, beta 2-microglobulin, the immunoglobulin light chains, and MAUP (most acid urinary protein). The use and utility of internal-charge and molecular-mass standards are described. We used electrophoretic transfer of proteins to nitrocellulose sheets and subsequent detection by immunological methods to identify some proteins.