The mercury sphygmomanometer is the undisputed gold standard for the indirect measurement of blood pressure. Some public health advocates have recently expressed concern about the use of mercury in medical practice.2 This concern has prompted many medical facilities to replace mercury manometers with aneroid devices. The present report examined the performance of 282 aneroid sphygmomanometers in outpatient medical practices. Results were examined for predetermined end points within ±3 mm Hg from the reference values and to indicate zero at no pressure. Ninety-three devices (33%) failed to perform at ≥1 pressure levels. Most (76%) of the failures were due to low readings. Only 7 of the 93 failing units did not rest at zero, making this an unreliable indicator of accuracy. Inaccurate readings of aneroid sphygmomanometers may result in a failure to diagnose and treat hypertension, thereby placing hypertensive patients at risk for end-organ damage and cardiovascular events.