Quantitative analysis system of leukotriene B4, C4, D4 (LTB4, LTC4, LTD4), and 5-hydroxyeicosatetraenoic acid (5-HETE) by reverse-phase high-performance liquid chromatography was developed. The lower limit of detection was 1 ng of each compound with a very close correlation between the amount of each compound and its peak height. Normal peripheral blood polymorphonuclear leukocytes (PMN) stimulated with Ca ionophore A23187, produced detectable amounts of LTB4, LTC4, and 5-HETE, but no LTD4 was produced in this condition. This analysis system was useful for measuring LTB4, LTC4, LTD4, and HETEs from the biological samples.