Arachidonic acid (AA) can be metabolized in endothelial cells (EC) to a series of epoxides via cytochrome P-450 epoxygenase with 14,15 epoxyeicosatrienoic acid (14,15-EET) as the major product. In this communication we report that 14,15-EET significantly enhances U937 cell attachment to EC with maximal cell attachment at 2.5 to 5 x 10(-7) M 14,15-EET. Thus, 14,15-EET may play a substantial role in inflammation and/or atherogenesis by inducing monocyte attachment to EC.