Abstract Objective: Elevated blood pressure and tobacco smoking are causes of preventable mortality. The effects of tobacco smoking on blood pressure are complex and chronic effects of tobacco smoking are inconsistent. We reported that DNA damage was increased in smokers’ blood cells compared to non-smokers. Recently, it has been reported that DNA damage is involved in cellular senescence. In this study, we investigated whether cigarette smoke extract (CSE) exerts DNA damage and cellular senescence in endothelial cells and the physiological influence of DNA damage. Design and method: The effect of CSE extracted from tobacco smoke was examined in human umbilical vein endothelial cells (HUVEC). CSE was added to HUVEC and DNA damage formation was quantified by fluorescence immunostaining; DNA single strand breaks (SSBs) with RPA 2 and double-strand breaks (DSBs) with phosphorylated histone H2AX as indices. Cellular senescence was quantified by senescence-associated -b galactosidase activity. The mRNA expression of inflammatory cytokines was quantified by real-time RT PCR. Results: SSBs increased at 24 hours after CSE stimulation, and DSBs increased significantly at 72 hours after stimulation. Continuous stimulation with CSE for 7 days resulted in an accumulation of cytosolic DNA (percentage of cells with cytosolic DNA; control: 3.4 ± 1.1, 7 days stimulation: 11.8 ± 1.8, p < 0.01)and accelerated cellular senescence (percentage of senescent cells; control: 32.5 ± 3.4, 7 days stimulation: 61.5 ± 5.2, p < 0.01). The mRNA expression of inflammatory cytokines, such as IL-6 and IL-1a was increased and prolonged by continuous CSE stimulation. Conclusions: CSE was shown to induce DNA damage, accumulation of cytosolic DNA, cellular senescence and inflammation of vascular endothelial cells.