The adherence of clinical isolates of staphylococci to surfaces immobilized with various glycosaminoglycans (GAGs) was studied. In general, cells of strains of coagulase-negative (CNS) staphylococci showed a greater adherence to polyethylene surfaces than did cells of Staphylococcus aureus, as studied by bioluminescence. When the surface was heparinized, the adherence of staphylococcal cells decreased, but CNS cells still adhered in greater numbers than did cells of S. aureus. The adherence of CNS to serum-coated heparinized surfaces was of the same magnitude, or increased compared with nonheparinized surfaces. When the surfaces were preadsorbed with different proteins with known heparin-binding domains, i.e., vitronectin, fibronectin, laminin, or collagen, the S. epidermidis cells showed higher binding to heparinized surfaces than to nonheparinized ones, and also in greater numbers than did other staphylococcal cells. Different CNS strains showed a greater ability to agglutinate polystyrene beads immobilized with heparin than did S. aureus. The adherence of S. epidermidis strain 3380 to polyethylene coated with various GAGs such as heparin and chondroitin, dextran, dermatan, and heparan sulfate was shown to be pH-dependent, with the highest adherence at pH 7.2. This may indicate that CNS have the ability to bind to other domains of host proteins when they are adsorbed to heparinized surfaces, versus to nonheparinized ones.