The aim of the present study was to investigate the full range of aortic root diameters and stiffness in a group of subjects without known cardiovascular risk factors and/or overt cardiovascular disease. Four hundred and twenty-two healthy subjects (mean age 44.35 ± 16.91 years, range 16 to 90, 284 men [67%]) underwent comprehensive transthoracic echocardiography. The leading edge method was used for the end-diastolic aortic root diameters measured at 4 locations (1) the aortic annulus, (2) the sinuses of Valsalva, (3) the sinotubular junction, and (4) the maximum diameter of the proximal ascending aorta. Aortic wall stiffness was assessed using 2-dimensional guided M-mode evaluation of systolic and diastolic aortic diameter, 3 cm above the aortic valve. The absolute aortic root diameters increased with age in both genders. Aortic measurements were significantly greater in men than in women at all levels, whereas body surface area–indexed values were similar in men and women, except for the ascending aorta for which women tended to have greater values. Multivariable regression analysis using age and body size (weight, height, and body surface area) predicted all aortic diameters, whereas blood pressure indexes predicted only the distal part of the aorta. Aortic stiffness increased with age in men and women with no differences between genders; only age predicted aortic stiffness. The increment in aortic diameter with age was lesser when adjusted for aortic stiffness. In conclusion, we define the physiologic range of aortic root diameters and related stiffness in healthy subjects stratified by age and gender. Moreover, aortic stiffness should also be taken into account when the increase of aortic diameter is considered.