Low Pressure carburising often combined with High Pressure Gas Quenching has become competing technology to the since decades well-known conventional carburizing processes. A certain amount of risk, at least from the user's point of view, is the lack of detailed background information. Since this technology is still in a development stage the influence of the process parameters on material properties and life-cycle time is not completely investigated yet. One phenomenon that is dreaded among the people in this branch is the hydrogen-embrittlement-induced-cracking that often leads to total failure of the part. The aim of this investigation was to find out how big the hydrogen intake up during low pressure carburizing in comparison with the traditional gas carburizing processes is. For this purpose 4 different case hardening steels (20MnCr5, 20MnCrS5, 18CrNiMo7-6 and 25MoCr4) has been first tempered to bring all samples into the same initial state followed by a low pressure carburising process. The process parameters were defined in the way that the surface carbon content should end up to 0.7 Conc.-% by a carburizing depth of 0.6mm. The influence of steel grade, carburizing gas (propane and acetylene), pressure and process time was evaluated and will be discussed in the paper. Finally the resulting hydrogen content of the treated samples, measured by the hot-gas extraction method, were compared with typical values for the conventional gas carburizing process out of the literature.