Leukocyte ingress into the synovium is a key process in the pathogenesis of rheumatoid arthritis and other inflammatory conditions. In this review, the role of endothelial cells in leukocyte extravasation will be discussed, including the role of the most relevant cellular adhesion molecules. These molecules play an important role in mediating leukocyte--endothelial interactions. It is likely that different adhesive pathways are involved in different steps of leukocyte adhesion to and migration through endothelia. Targeting of pathological endothelial function, including leukocyte--endothelial adhesion, may be useful for the future management of inflammatory arthritis.