Certain immunocompetent myeloid cells, such as eosinophils, basophils and mast cells, have a large capacity to synthesize the potent proinflammatory and spasmogenic mediator leukotriene (LT) C₄ via a specific microsomal glutathione S‐transferase (MGST) termed LTC₄ synthase (LTC4S). Here, we report that MGST2, a distant homologue of LTC4S, is abundantly expressed in Human umbilical vein endothelial cells (HUVEC) and converts LTA₄ into a single product, LTC₄. Thus, using Northern blot, RT‐PCR, Western blot, and enzyme activity assays, we show that MGST2 is the main, if not the only, enzyme that converts LTA₄ into LTC₄ in membrane preparations of HUVEC. In fact, we failed to detect any expression of LTC4S, MGST1 or MGST3 in these cells, indicating that MGST2 is a critical enzyme for transcellular LTC₄ biosynthesis in the vascular wall. Unlike LTC4S, MGST2 prefers the naturally occurring free acid of LTA₄ over the methyl ester as substrate and is also susceptible to product inhibition with an IC₅₀ of about 1 µm for LTC₄. Moreover, HUVEC were found to express the CysLT₁ receptor in line with a paracrine and autocrine role for cysteinyl‐leukotrienes in endothelial cell function.