Abstract: A cup-shaped sintered metal ultra-high efficiency filter which is capable of achieving of at least 99.9999999% efficiency at a most penetrating particle size at the maximum rated flow is produced using a metal powder with particles of less than 20 micrometers in diameter in a mold having a cylindrical cavity with an end closure at one end and a removable cap at its other end. A core rod is seated in the end closure and extends coaxially within the cavity with its upper end disposed at a predetermined distance from the open end of the mold. The mold is oriented vertically with the open other end disposed upwardly, and metal powder is introduced into the cavity while vibrating the mold to achieve substantially uniform packing of the metal powder to a level above the core rod.