Interaction between gametes during fertilization is at least in part regulated by carbohydrate moieties of the zona pellucida (ZP) and carbohydrate binding proteins of the sperm surface. This review focuses on the protein-carbohydrate interactions during the primary binding of the sperm to the ZP in different species. Synthesis, structure and composition of the ZP are summarized. The functional significance of carbohydrate residues of the ZP as sperm receptor is discussed. Sperm surface proteins known to have specific ZP and carbohydrate-binding sites including the mouse beta1, 4-galactosyltransferase and sp56, the rabbit protein Sp17, a human mannose-binding protein and several members of the spermadhesin family are presented.