Abstract: A ball valve operative in a cryogenic temperature range, includes a housing having a fluid passage therethrough, a ball rotatably positioned in the fluid passage and including a fluid passage therethough, the fluid passages of the housing and the ball allowing fluid through the ball valve when the ball is in an open position and block the fluid when the ball is rotated into a closed position. The housing includes at least two sealing rings disposed therein, sealingly contacting the ball and positioned for rotatably holding the ball between the two sealing rings which include at least a surface layer of thermoplastic material contacting the ball surface and having an annular, circumferential groove in a contacting surface where the rings sealingly engage the ball and an annular recess in the sealing ring opposite to the circumferential groove for providing a spring lip for biasing the sealing ring against the ball.