Since 1986, a series of international interlaboratory comparisons on the evaluation of mechanical properties of cryogenic structural materials have been performed among the participants of VAMAS (the Versailles Project on Advanced Materials and Standards) TWA (Technical Working Area) 17 in order to establish unified test methods. Through these international collaborations and Round-Robin Tests (RRTs), we have accumulated knowledge about mechanical tests at 4 K, and have prepared a draft of an international standard for tensile testing in liquid helium. The draft was submitted to ISO TC164/SCI as a new work item, and testing conditions, strain measurements, and other technical points have been discussed. The outline, development, and discussion of the document so far, with the results of RRTs, are presented. Objectives of other international standardization programs on mechanical testing in high magnetic field, J-Evaluation on Tensile Test, and for composite material are summarized also in this paper. ©2002 American Institute of Physics.