A high-speed reciprocating wear test rig with moisture control facilities has been further developed for undertaking wear tests in hydrogen environments with moisture content of 1 - 1,OOOppmV to evaluate the wear performance of four commercial compressor seal materials. The test results are presented and compared to those obtained in nitrogen environment, where available. It was found that the wear rate and the friction coefficient of sample A increased significantly as moisture content decreased below -1 50ppmV, whilst the other three samples showed much less or no dependence of the wear rates and the friction coefficients upon moisture content.