We labeled surface glycoproteins of normal human blood platelets, granulocytes, monocytes, T and B lymphocytes, and null cells by the galactose oxidase-NaB3H4 and periodate-NaB3H4 labeling techniques. The labeled glycoproteins were observed by fluorography after separation by polyacrylamide slab gel electrophoresis. All major types of human leukocytes showed different and characteristic surface glycoprotein patterns. These patterns evidently also include common components.