Selectins are carbohydrate-binding proteins and responsible for leukocyte extravasation in inflammation. Here we demonstrate the potential of synthetic glycocompounds as inhibitors for the selectin-ligand interaction. Pentaerythritol derivatives showed distinct selectin-binding properties with IC50 values up to 1.5 mu M. Multivalent hyperbranched polyglycerol (hPG) derivatives did not lead to a substantial increase in inhibition, but a more than 1000-fold enhancement was realized when sulfated glyco-hPGs were tested. IC50 values in the high picomolar to low nanomolar range were obtained for selectin inhibition, which highlights the relevance of sulfate groups that seem to dominate the binding mode.