Objectives Endothelial dysfunction is the earliest marker for atherosclerosis and plays key role in the pathogenesis of cardiovascular diseases. The present study was performed to evaluate effect of aging on arterial elasticity by using pulse waveform analysis and investigate whether the changes in arterial elasticity can be used as a non - invasive measure for early detection of endothelial dysfunction. Methods Using modified Windkessel model of the circulation and pulse waveform analysis, C1 large ar- tery and C2 small artery elasticity indices of 204 normal healthy subjects ( age 15-80 years) were measured. Among them twenty - four male healthy subjects were divided into both the young ( age 20 - 30 years, n = 12) and elderly (age 60 -70 years, n = 12) groups. We delivered acethycholine (Ach) , an endothelium - dependent vasodilator, and sodium nitroprusside (SNP) , an endothelium - independent vasodilator, to dermal vessels of the forearm using iontophoresis, re- spectively, and measured basal and peak blood flow u- sing laser doppler fluximetry. Results Cl large ar- tery and C2 small artery elasticity indices were reduced with advancing age. C1 large artery and C2 small arter- y elasticity indices were negatively correlated with age (r= -0.628, p<0.001; r= -0.595, p<0.001). Basal blood flow was similar between the young andelderly groups (14. 58 ±3.4 vs 13. 52 ±3.41 PU, p = NS). Peak blood flow induced by Ach was significandy reduced in the elderly group compared with the young group (83.4 ±11.9 vs 93.75 ±10.87 PU, p <0.05). However, peak blood flow induced by SNP was similar in the two groups (119.17 ± 16.76 vs 128. 33 ±21. 29 PU, p = NS ) . Ach - induced peak blood flow correlated pos- itively with C1 large artery and C2 small artery elasticity indices(r = 0. 56, p < 0. 01; r =0.53, p < 0.01). Conclusions Advancing age leads to impaired artery elasticity and endothelial dysfunction. Reduced arterial elasticity is, in parallel, associated with diminished endothelium - dependent vasodilation. It is concluded that arterial elasticity assessment provides a non - inva- sive measure for the early evaluation of vascular endo- thelial function. Objectives Endothelial dysfunction is the earliest marker for atherosclerosis and plays a key role in the pathogenesis of cardiovascular diseases. The present study was performed to evaluate effect of aging on arterial elasticity by using pulse waveform analysis and investigate whether the changes in arterial elasticity can be used as a non-invasive measure for early detection of endothelial dysfunction. Methods Using modified Windkessel model of the circulation and pulse waveform analysis, C1 large ar- tery and C2 small artery elasticity indices of 204 normal healthy subjects (age 15-80 years) were measured . Among them twenty - four male healthy subjects were divided into both the young (age 20-30 years, n = 12) and elderly (age 60-70 years, n = 12) groups. We delivered acethycholine (Ach), an endothelium - dependent vasodilator, and sodium nitroprusside (SNP), an endothelium - independent vasodilator, to dermal vessels of the forearm using iontophoresis, re- spectively, and me Results Cl large ar- tery and C2 small artery elasticity indices were reduced with advancing age. C1 large artery and C2 small arter- y elasticity indices were negatively correlated with age (r = -0.628, p <0.001; r = -0.595, p <0.001) .Basal blood flow was similar between the young andelderly groups (14. 58 ± 3.4 vs 13. 52 ± 3.41 PU, p = NS) by Ach was significantly reduced in the elderly group compared with the young group (83.4 ± 11.9 vs. 93.75 ± 10.87 PU, p <0.05). However, peak blood flow induced by SNP was similar in the two groups (119.17 ± 16.76 vs 128. 33 ± 21 29 PU, p = NS). Ach - induced peak blood flow correlated positively with C1 large artery and C2 small artery elasticity indices (r = 0.56, p <0.01; r = 0.53, p <0.01). Conclusions Advancing age leads to impaired artery elasticity and endothelial dysfunction. Reduced arterial elasticity is, in parallel, associated with diminished endothelium - dependent vasodilation. It is concluded that arterial elasticity assessment provides a non - inva- size measure for the early evaluation of vascular endothelial function.