Abstract: A cardiac valve comprises a plurality of flexible trapezoidal membranes, each having an edge joined to an edge of another of the membranes to form an unsupported frusto-conical body. The body has an oval end portion and a plurality of flexible flap portions integral with and extending from the end portions, the flap portions being formed by substantially parabolic scallops. The membranes are so sized, and the scallops are so positioned as to form flap portions of unequal size. The flexible membranes may be provided to the surgeon as separate membranes for construction of the artificial valve, or the valve may be provided to the surgeon as a complete unit. Alternatively, the surgeon may construct a valve using pericardium mapped and sized in accordance with the present invention.