The high-iron diamine staining (HID), which has been used in histochemistry to stain sulfated glycoconjugates (SGC), was tested for detectability of authentic acidic substances (chondroitin sulfates A plus C, dermatan sulfate, heparan sulfate, chondroitin, hyaluronic acid, alpha 1-acid glycoprotein and ribonucleic acid) in electrophoresis on cellulose acetate membrane (Separax). The results showed that only SGC were detectable by the HID, although all the above substances were stained with alcian blue. The glycoconjugate preparations obtained from the liver, kidney, lung, small intestine, colon, stomach, brain and spleen of rats were examined by two-dimensional electrophoresis on Separax. The new spots (or bands), besides those of sulfated glycosaminoglycans, were detected by the HID on the electrophoretograms of all the samples except for the kidney one. The substances giving the new spots (or bands) were indicated to be sulfated glycopeptides (SGP) by crude heparinase digestion of a representative sample. The present results revealed that the HID was applicable for detection of SGP in electrophoresis on cellulose acetate membrane. Also, it is a novel finding that the liver and spleen contain SGP.