The damage of vascular endothelial cells leads to the progression of vascular disease. Apoptotic damage of endothelial cells is an important mechanism in vascular disease. Recently, it has been reported that radiocontrast can induce vascular endothelial cell injury. The present study used terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) and FACScan analysis to examine whether radiocontrast agenst, such as iopromide, sodium-meglumine-ioxithalamate or gadopentetate dimeglumine,induce apoptotic injury in human umbilical vein endothelial cells. In the study, iopromide, sodium-meglumine-ioxithalamate and gadopentetate dimeglumine brought about human umbilical vein endothelial cell death in phase-contrast microscopic findings. According to TUNEL and FACScan analysis, iopromide and sodium-meglumine- ioxithalamate induced apoptosis in vascular endothelial cells in a dose-dependent. The apoptotic effect of sodium-meglumine-ioxithalamate was shown to be greater than that of iopromide. Gadopentetate dimeglumine also induced apoptosisin human umbilical vein endothelial cells as observed by TUNEL and FACScan analysis. These results suggest that iopromide, which is a non-ionic radiocontrast agent, proved to be less apoptotic than sodium-meglumine-ioxithalamate. Gadopentetate dimeglumine, which is used MRI, has an apoptotic effect in vascular endothelial cells. Thus, apoptosis of endothelial cells by radiocontrast agents might induce deleterious effects on vascular endothelial integrity.