Aim The effect of oxidized low density lipoprotein (OLDL) on adhesion of monocytes to cultured pig aortic endothelial cell (EC), expression of granule membrane protein l40 (GMP-140) and secretion of prostacyclin (PGI2)was studied.Methods Adhesion of monocytes to EC was determined with Terrio' s assay.Expression of GMP-140and secretion of PGI2 were detected the use of enzymelinked immunosorbent assay (ELISA).Results It was found that oxidized low density lipoprotein enhanced the adhesion of monocytes to EC in a dose-dependent and time-relative manner. Adhesion increased with increasing concentration of oxidized low density lipoprotein up to 100 mg protein/L and then levelled off. There was an initial but not significant increase in adhesion seen half an hour after exposure, a abvious rise at 1h and up to a maximum at 3 h.There after, the adhesion level decreased.Meanwhile,oxidized low density lipoprotein(100 mg/L)enhanced the amount of GMP-140 on EC membrane from 92.8±47.6 to 293.0±140.7μg/L(P<0.05) , but a inpaired EC secretion in PGI2 from 84.6±8.7 to 6.0±3.1ng/L (P<0.01).Conclusions These results indicate that oxidized low density lipoprotein may enhance th interaction between monocytes and EC via the adhesion molecular,GMP140.