The purpose of this study is to provide standard echocardiographic and morphometric data for normal mouse valve structure and function from late fetal to aged adult stages. Cross sectional, two-dimensional and Doppler transthoracic echocardiography was performed in C57BL6 mice anesthetized with 1-2% Isofluorane at embryonic day 18.5 (late fetal), 10 days (neonate), 1 month (juvenile), 2 months (young adult), 9 months (old adult), and 16 months (aged adult). Normal annulus dimensions indexed to age or weight and selected flow velocities were established by echocardiography. After echocardiographic imaging, hearts were harvested and histologic and morphometric analyses were performed. Morphometric analysis demonstrated progressive valve thinning and elongation during the fetal and juvenile stages that plateaued during adult stages (ANOVA p<0.01); however, there was increased thickening of the hinge of the aortic valve annulus with advanced age reminiscent of human aortic valve sclerosis. There was no age-related calcification. The results of this study provide comprehensive echocardiographic and morphometric data for normal mouse valve structure and function from late fetal to aged adult stages, and should prove useful as a reference standard for future studies utilizing mouse models of progressive valve disease.