Abstract: Devices to measure the blood pressure of patients are being used without any calibration in a hospital.It is an important to show consistent values when any medical devices measure the same patients regardless theyare sphygmomanometer or fully automatic electronic blood pressure meter. We compared sphygmomanometer andfully automatic electronic blood pressure meters with standard digital blood pressure monitor (SDBPM) to evaluatethe consistency of the small healthy subjects. We measured the blood pressure from six healthy subjects (three of20~40 years and three of 40~60 years old). Two sphygmomanometer and two fully automatic electronic blood pres-sure meters were used and compared with the SDBPM. Blood pressures measured from right and left arms eachand were compared. All six healthy subjects showed normal blood pressure values. In general, left blood pressurevalues showed higher values than right side. Comparing SDBPM, with the other monitors, the systolic pressureshowed ± 34.8% difference and ± 33.3% for the diastolic pressure. Correlation between SDBPM and Sphygmoma-nometer was 0.59~0.71, and 0.50~0.70 for fully automated digital BP monitors. It fell in grade-D when we applythe BHS(British hypertension society). AAMI(American association for the advancement of medical instrumentation)also showed unsatisfactory results for the mean value (≤ 5 mmHg) and standard deviation (≤ 8 mmHg). We testedsphygmomanometer and fully automatic electronic blood pressure meters and compared with a standard digital bloodpressure monitor. All devices showed inconsistent blood pressures. A reliable calibration system is highly neededfor all devices in all hospitals.Key words: Blood pressure, Sphygmomanometer, Fully automatic electronic blood pressure meters,Standard digital blood pressure monitor