Continuous flow, mechanical cardiac assist devices rely on a rotating impeller to aid the heart with blood flow. Like any other mechanical system, the rotating components of these devices require some form of load support that is provided by either mechanical or magnetic bearings. The goal of this article is to provide an overview of basic principles that are important for design and evaluation of mechanical bearings used in blood pumps with a primary focus on mechanical bearings used in the second and third generation ventricular assist devices (VADs). A general introduction of some basic...