Automated blood pressure devices have been embraced by clinicians for their convenience and ease of use. However, the pressure to remove mercury-containing medical devices is leading to the demise of the mercury sphygmomanometer and the loss of manual blood pressure measurement skills. The article argues that there is still a place for the mercury sphygmomanometer, particularly when a clinical decision is based on the blood pressure readings. It presents a review of the available literature to explain the rationale for the use of manual sphygmomanometry and gives a step-by-step guide to the procedure with current supporting evidence. There is a brief discussion of special considerations when dealing with certain client groups. Normal blood pressure ranges for adults and children have been included along with a definition of hypertension for both groups.