SCOPE: Cranberries are rich in potentially bioactive (poly)phenols. The aim of this work was to investigate whether cranberry juice intake can improve vascular function in healthy men in a dose- and time-dependent manner, and to understand which of the circulating (poly)phenol metabolites correlate with vascular effects. METHODS AND RESULTS: A double-blind randomized controlled crossover trial was conducted in 10 healthy males. Flow-mediated dilation (FMD), blood pressure, pulse wave velocity and augmentation index were investigated at baseline, 1, 2, 4, 6, and 8h post-consumption of cranberry juices containing 409, 787, 1238, 1534, and 1910 mg of total cranberry (poly)phenols (TP), and a control drink. Plasma (poly)phenol metabolites were analyzed by UPLC-Q-TOF MS using authentic standards. We observed dose-dependent increases in FMD at 1, 2, 4, 6, and 8h with a peak at 4h and maximal effects with juice containing 1238 mg TP. A total of 60 metabolites were quantified in plasma after cranberry consumption. Twelve (poly)phenol metabolites significantly correlated with the increases in FMD, including ferulic and caffeic acid sulfates, quercetin-3-O-s-D-glucuronide and a gamma-valerolactone sulfate. CONCLUSION: (Poly)phenols in cranberry juice can improve vascular function in healthy males and this is linked to the presence of specific newly identified plasma metabolites.