Austenitic stainless steel alloys 304L, 316, 316L and 201LN were evaluated using rotating-beam testing techniques to evaluate the influence of internal hydrogen on the fatigue response for these commercially important structural materials. Two conditions were evaluated: samples that had not been exposed to hydrogen and samples that had been thermally precharged in hydrogen. Uniaxial tensile testing shows that all alloys are strengthened by high concentration of internal hydrogen and the tensile ductility is significantly reduced. High-cycle fatigue life, on the other hand, was 10-100 times greater with internal hydrogen compared to the as-received material, in agreement with previously reported results. When the fatigue data are normalized by the yield strength, the fatigue limit is essentially unaffected by hydrogen precharging.