Echocardiography is the cornerstone in the diagnosis of any valvular heart disease. The accurate diagnosis of aortic stenosis, the left ventricle function and the other heart valves evaluation are currently done by ultrasound alone. Prosthetic valve choice and dimensions prior to implantation can be done solely by proper use of echocardiography. The emergence of new methods to cure aortic stenosis such as trans-catheter aortic valve replacement (TAVR) emphasized the diagnostic value of cardiac ultrasound. The usefulness of echocardiography in TAVR can be divided in the baseline assessment (common to patients treated by conventional surgery), intra-procedural guidance of valve deployment and post-procedural follow-up. In the baseline diagnostic work-up echocardiography should allow proper assessment of low-gradient severe aortic stenosis and especially of "low-flow, low-gradient" aortic stenosis, as far the benefit of any valve intervention in these cases may be overshadowed by persistent ventricular dysfunction. "Classic" TAVR is performed with a trans-esophageal echocardiography probe in place, but recently intracardiac echocardiography (ICE) was advocated to reduce the need for general anesthesia. "Minimalist TAVR approach" recommends no echo-guidance and valve implantation by angiography alone. Post-TAVR echo assessment should allow prompt recognition of early complications and the severity of para-valvular leaks. Long term follow-up by echocardiography assesses prosthetic valve function, left ventricular functional recovery and the impact of the procedure on associated conditions (mitral regurgitation, pulmonary hypertension or tricuspid regurgitation). This article emphasizes the role of the cardiologist with ultrasound skills in the assessment of patients addressed to TAVR.