Recently, it has been well-known that various materials produced by metal injection molding(MIM) process show the excellent mechanical properties which are normally evaluated by the static rupture test such as tensile test. However, the assesment of the dynamic rupture properties such as fatigue strength is more important for the practical machine parts.In this study, the behavior of fatigue properties for a stainless steel (SUS316L) produced by MIM process were investigated taking the process conditions and microstructures into account. The fatigue strength of hydrogen sintered steels were higher than that of the vacuum sintered steels. This seemed to be due to the difference of pore distribution in the surface and inside between the hydrogen and vacuum sintered steels. Both tensile and fatigue strength of hydrogen sintered steels which had still not the full density were equivalent to those of the wrought steels. This result indicates that the MIM process is applicable to high performance machine structural parts required high static and dynamic strength as well.