BACKGROUND To evaluate the accuracy of the OMRON-MIT, (an automated inflationary oscillometric blood pressure monitoring device) for use in the general population by direct comparison to standard auscultatory mercury sphygmomanometry. METHODS Two trained, blinded observers taking simultaneous blood pressure measurements alternating between a mercury sphygmomanometer and the OMRON-MIT. METHODS The evaluation was carried out according to the revised British Hypertension Society protocol. The validation data was also classified by the American Association for the Advancement of Medical Instrumentation (AAMI). RESULTS The OMRON-MIT device achieved a BHS grade A for both systolic blood pressure (SBP) and diastolic blood pressure (DBP). It also met the criteria for the AAMI protocol, the mean difference between the MIT and standard was -2.0 +/- 7 mmHg for SBP and -2.0 +/- 6 mmHg for DBP. CONCLUSIONS Inflationary oscillometry is a valid technique for the measurement of blood pressure. The OMRON-MIT, which uses this technique, is accurate and can be recommended for clinical use in the adult population.