We have isolated cDNA clones corresponding to the human erythrocyte membrane sialoglycoprotein beta. The clones encompass the coding region for the protein, 120 residues of the 5' non-coding region and the 3' non-coding region. The cDNA sequence suggests that sialoglycoprotein beta is not translated with the cleaved N-terminal signal sequence usual in a membrane protein of this type. Sialoglycoprotein beta or a closely related homologue is present in human kidney as well as erythroid cells.