In the development of hydrogen technology, special attention is paid to the technical problems of hydrogen storage. One possible way is cryogenic storage in liquid form. Generally cryotechnical machines need components with interacting surfaces in relative motion such as bearings, seals or valves, which are subjected to extreme conditions. Materials of such systems have to be resistant to friction-caused mechanical deformation at the surface, low temperatures and hydrogen environment. Since materials failure can cause uncontrolled escape of hydrogen, new material requirements are involved for these tribo-systems, in particular regarding operability and reliability. In the past few years several projects dealing with the influence of hydrogen on the tribological properties of friction couples were conducted at the Federal Institute for Materials Research and Testing, (BAM), Berlin. This paper reports some investigations carried out with polymer composites. Friction and wear were measured for continuous sliding and analyses of the worn surfaces were performed after the experiments. Tests were performed at room temperature in hydrogen as well as in liquid hydrogen.