Abstract: A process for making an integral one piece rotor liner for use with a high speed rotor. The liner has an inner chamber and an annular chamber designed to operate in conjunction with the rotor operation to automatically allow fluid communication between the respective chambers during centrifugation and automatically establish a seal between the respective chambers subsequent to the centrifugation operation. The process for making the one piece rotor liner generally comprises a first step of molding the liner in an intermediate elongated configuration wherein the inner chamber portion is integrally joined to and spaced from the annular chamber portion of the liner by a reversing section. The general configuration of the inner chamber is located at one end of the elongated liner shape and the general configuration of the annular chamber is located at the other end of the elongated liner.