Purpose : The purpose of this study was to determine the value of the intrarenal resistive index (RI),measured by Doppler sonography, in order to assess intrarenal vascular resistance in autosomal dominant polycystic kidney disease (ADPKD) patients. Materials and Methods : In 26 patients with ADPKD, RI was measured by Doppler sonography and correlated with the presence of hypertension, renal function (creatinine clearance) and anatomical renal severity index (RSI), thus indicating renal morphologic abnormalities during B-mode sonography. Results :RI was significantly higher in 18 hypertensive ADPKD patients (0.64$pm$0.65) (Mean$pm$1SD; range: 0.52-0.74) than in eight normotensive patients (0.59$pm$0.50) ( 0.48-0.64) (p<0.05). Statistically significant inverse correlation was found between RI values and creatinine clearance (r=-0.45, p<0.05), and statistically significant correlation was found between RI values and RSI, indicating the degree of renal parenchymal involvement. Conclusion : RI correlates with the development of hypertension, renal function and renal morphologic abnormality scoring by RSI during B-mode Doppler sonography, and measured in this way may thus be used to assess renal vascular resistance in ADPRD patients.