Objective: Aortic stenosis (AS) and arterial hypertension often clusterize and increase cardiovascular disease burden. Renal artery (RA) stenosis, the main form of secondary hypertension, can act as an upstream factor of resistance at the same way of AS. Aim of the study: to investigate if the presence of AS is able to interfere with the ultrasound (US) parameters in the diagnosis of RA stenosis. Design and method: In hypertensive subjects with AS we evaluated US indirect parenchymal parameters: resistive index (RI) and index of maximal systolic acceleration (AImax: the maximal acceleration of flow waveform in early systole divided by the peak systolic velocity), and US direct RA parameters: peak systolic velocity (PSV) and Renal/Aortic Ratio (RAR). Results: We compared hypertensive patients (mean age 74 years) with preserved left ventricular function with severe AS (n=18) or mild AS (n=21). No statistically differences were detected between groups regarding gender, age, smoke, ABI, CV risk factors, lipids, and renal function. Direct US parameters of RA did not differ significantly between patients with severe or mild AS (mean PSV 113 vs 127 cm/sec; mean RAR 1.3 vs 1.6). RI showed the same behavior (0.75 vs 0.73). AImax was significantly lower in patients with severe vs mild AS (8.74 vs 15.56 1/sec, p<0.0005). We found an inverse correlation between AImax and the mean (r2=0.435) and peak (r2=0.424) transvalvular gradient. Among 14 patients with severe AS underwent correction of valvular disease. At 6 months, US showed a significant increase in AImax (from 10.0 to 19.8 1/sec, p<0.005), while RI did not differ significantly (0.74 vs 0.73). Conclusions: Severe AS act as a proximal resistance that can attenuate the systolic acceleration phase of the flow profile of the renal intraparenchymal vessels, in particular of AImax, which is restored after surgical correction of the valve defect. Presence of AS may affect the diagnostic workup of RA stenosis.