Incubation of [3H]arachidonic acid with the 17,000-g supernatant from homogenates of human neutrophils in the presence of indomethacin generated the unique metabolites 9-OH-5,7,11,14-eicosatetraenoic acid (9-HETE) and 8-HETE, in addition to 12-HETE, 11-HETE and 5-HETE. The human neutrophil chemotactic activity of the HETE products exhibited a rank-order of potency with 5-HETE greater than 8-HETE = 9-HETE greater than 11-HETE = 12-HETE. The expression of chemokinetic activity as well as chemotactic activity suggested that the endogenous production of these principles may influence the mobility of human neutrophils.