Malonic acid derivatives designed as mimetics of the sialyl Lewis X determinant were synthesized. Their inhibitory potency for selectin mediated cell adhesion was evaluated in cell culture assays and in vivo. The receptor binding affinity for E- and P-selectins of simple mimetics was found to be comparable to the potency of the tetrasaccharide sialyl Lewis X. (C) 1997 Elsevier Science Ltd.