Objective: Low testosterone levels and increased aortic stiffness are predictors of cardiovascular events. The influence of androgen level on the age-and blood pressure-related increase in aortic stiffness is unknown. Methods: From January 2007 to June 2011 we enrolled 455 consecutive men with no evidence of cardiovascular disease from a large cohort followed in our Department for arterial function studies. Their total testosterone (TT) levels were measured and carotid-femoral pulse wave velocity (PWVc-f) was measured as an index of aortic stiffness. Results: In multivariable analysis, PWVc-f values were inversely correlated to TT after adjustment for confounders (beta = -0.365, P < 0.001). In younger age categories (<50 yrs and 50-59 yrs), patients with testosterone deficiency (TD) had higher blood pressure-adjusted PWVc-f (P108 mmHg), patients with TD had higher age-adjusted PWVc-f (P < 0.001) compared to subjects with normal TT, indicating a synergistic unfavorable effect of testosterone deficiency and blood pressure on aortic stiffness. Conclusions: TT levels are independently associated with aortic stiffening. The effect of low testosterone concentration on aortic stiffness is more prominent in young men and in subjects with higher blood pressure levels. These findings identify testosterone as a marker of arterial damage with special emphasis on young and hypertensive individuals and support its role as predictor of events. (C) 2014 Published by Elsevier Ireland Ltd.