During the past years high pressure gas quenching was a very actual subject at different conferences. There were a lot of lectures which used heat transfer coefficient as the most important parameter for the characterization of a gas quenching system. This statement is surely correct, but only fully utilizable—for example, for the comparison of measurements from different authors—when a well defined measurement method was used. Up to 2002 this was not realized. To solve this problem on a national basis the German Research Committee for Quenching has delt with this subject in the period from 1998 to 2002. In a first step the possibly influencing parameters were identified. In a second step most of the parameters were predefined. In a few cases there was no information about the magnitude of the possible influence available (example: evaluation procedure). To answer these remaining questions a round-robin test was carried out. The participants were the companies Ipsen International and Dr. Sommer Werkstofftechnik, Germany, and the institutes IVF Sweden and IWT Bremen, Germany. The results of this work were published in 2002 in the German heat treatment journal HTM including a recommendation for the measurement of heat transfer coefficient at gas quenching (in German language). This paper is a translation of this work and shall help to solve the above-mentioned problem on an international level.