Background and aims Autosomal-dominant polycystic kidney disease (ADPKD) is one of the most common causes of end-stage renal disease (ESRD). The most important cause of death among ADPKD patients is cardiovascular (CV). The aim of this study was to examine the prognostic significance of arterial stiffness on CV and renal outcomes in ADPKD. Methods A total of 55 patients with ADPKD were examined. Pulse wave velocity was determined and stiffness index (SIDVP) was calculated. Combined primary endpoints (CV and renal) were major CV events (myocardial infarction, stroke, and CV intervention) as CV endpoints, and attaining of ESRD or start of renal replacement therapy as renal endpoints. Secondary endpoints were CV or renal endpoints separately. Results The mean age of those 55 ADPKD patients was 45 ± 12years, 21 patients were male. The average value of the SIDVP was 11.11 ± 2.22m/s. The patients were divided into two groups by the cutoff value of 11m/s of SIDVP and then outcomes were analyzed. In the higher arterial stiffness group (SIDVP > 11m/s), occurrence of combined primary endpoint (CV and renal) was significantly higher than in the group with more elastic arteries (p = 0.033). A statistically significant difference was found in the renal endpoints (p = 0.018), but not in the CV endpoints (p = 0.952) between the two groups. Conclusions Increased arterial stiffness predicts the onset of ESRD in ADPDK. Assessment of SIDVP appears to be a useful method for estimating the renal and CV prognosis in ADPKD.