The ankle-brachial index (ABI) is a method used widely for peripheral arterial disease (PAD) diagnosis and cardiovascular risk prediction. This study validated automated ABI measurements taken using an oscillometric blood pressure (BP) monitor allowing simultaneous arm–leg BP measurements. A total of 93 patients (hypertension 83%; dyslipidemia 72%; diabetes 45%; cardiovascular disease 23%; smoking 15%) were submitted to Doppler and automated ABI measurements, performed using a professional oscillometric BP monitor (Microlife WatchBP Office; triplicate simultaneous arm–leg BP measurements), in a randomized order. The mean difference between the Doppler reading (1.08±0.17) and (1) the first oscillometric ABI reading was 0.03±0.11, (2) the average of two oscillometric readings was 0.02±0.10 and (3) the average of three oscillometric readings was 0.02±0.09 (Po0.01 for all). Strong correlations were found between oscillometric and Doppler ABI (r 0.80, 0.85 and 0.86 for single and average of two and three oscillometric readings, respectively; Po0.001 for all). Agreement between oscillometric and Doppler ABI in diagnosing PAD (Doppler ABI o0.9) was found in 95% of cases (j 0.79; agreement in diabetics: 94%, j 0.79). A receiver operating characteristic (ROC) curve revealed area under the curve at 0.98, with a 0.97 oscillometric ABI cutoff for optimal sensitivity (92%) and specificity (92%) in diagnosing PAD. Average time for automated ABI measurement was 5.8 vs. 9.3 min for Doppler (Po0.001). Doppler and oscillometric ABI were associated and predicted (multivariate regression analysis) by the same cardiovascular risk factors (pulse pressure, smoking and cardiovascular disease history). Automated ABI measurement using a professional BP monitor allowing simultaneous arm–leg BP measurements appears to be a reliable and faster alternative to Doppler measurement.