Glucocorticoids are well‐established anti‐inflammatory drugs thought to mainly act by inhibition of proinflammatory transcription factors like NFKB. In recent years, however, transcription factor‐independent mechanisms of glucocorticoid action have been proposed, namely the influence on MAPK pathways. Here we identify MAPK phosphatase‐1 (MKP‐1) as a pivotal mediator of the anti‐inflammatory action of glucocorticoids in the human endothelium. We applied dexamethasone (Dex) to TNF‐a‐activated human endothelial cells and used the adhesion molecule E‐selectin as inflammatory read‐out parameter. Dex is known to reduce the expression of E‐selectin, which is largely regulated by NF‐κB. Here, we communicate that Dex at low concentrations (1–100 nM) markedly attenuates E‐selectin expression without affecting NF‐κB. Importantly, Dex is able to increase the expression of MKP‐1, which causes an inactivation of TNF‐α‐induced p38 MAPK and mediates inhibition of E‐selectin expression. In endothelial MKP‐1^‐/‐cells differentiated from MKP‐1^‐/‐embryonic stem cells and in MKP‐1‐silenced human endothelial cells, Dex did not inhibit TNF‐α‐evoked E‐selectin expression. Thus, our findings introduce MKP‐1 as a novel and crucial mediator of the anti‐inflammatory action of glucocorticoids at low concentrations in the human endothelium and highlight MKP‐1 as an important and promising anti‐inflammatory drug target. Fürst, R., Schroeder, T., Eilken, H. M., Bubik, M. F., Kiemer, A. K., Stefan Zahler, S., Vollmar, A. M. MAPK phosphatase‐1 represents a novel anti‐inflammatory target of glucocorticoids in the human endothelium FASEB J. 21, 74–80 (2007)