We compared the repeatability of 2 ultrasonographic methods for endothelial function assessment at brachial artery-flow-mediated dilation (FMD) and post-ischemic peak blood flow (PBF). Twenty healthy volunteers were examined twice within 10 days; coefficients of variation were 13.8% for PBF and 41.0% for FMD. PBF seems to be superior to FMD in terms of reproducibility. Consequently, smaller noninvasive studies of endothelial function can be designed utilizing PBF compared with FMD.