BACKGROUND:We have developed a new blood pressure (BP)-measuring device with a double-cuff, and evaluated its accuracy and applicability for practical use. DESIGN:The double-cuff method features a small cuff placed in the centre of the compression cuff to detect the oscillation of arterial pulsation, by which algorithms for the determination of systolic BP (SBP) and diastolic BP (DBP) were rendered more objective than with the conventional oscillometric method. Algorithms for automatic BP determination were developed from the oscillation data taken with the small cuff from 217 men and 256 women, and then installed in the Terumo ES-H55 device (length: 17 cm, weight: 120 g). This ES-H55 device was tested on 87 subjects (65 hypertensives and 22 normotensives) to compare its accuracy with that of the auscultatory method according to the AAMI SP-10 protocol. RESULTS:Using Bland and Altman scatter plots, the difference in SBP between the ES-H55 device and the auscultatory method was within +/- 5 mmHg in 88% of subjects, and within +/- 10 mmHg in 97% (mean difference +/- SD: 0.2 +/- 3.9 mmHg). The difference in DBP was within +/- 5 mmHg in 80%, and within +/- 10 mmHg in 97% (difference: -0.1 +/- 4.6 mmHg). These results satisfied AAMI guidelines, and this device was easy to use. CONCLUSIONS:The ES-H55 device is compact and light, with clear algorithms for the determination of BP, and satisfies AAMI criteria, so that it is considered a useful BP-measuring device that could be used instead of a mercury sphygmomanometer by nurses and doctors in hospital wards.