Micro powder injection molding (muPIM), is a potential low-cost mass fabrication process for microstructures and micro-components. The process is adapted from the conventional powder injection molding (PIM) process. Various materials have been molded successfully by PIM into complex shape. Thus, muPIM could be used for many different materials (e.g., ceramics and metals) that can better meet the needs of a wide range of applications. This paper focuses on the production of 316L stainless steel microstructures by muPIM. Silicon mold insert produces by deep reactive ion etching is used and the molding conducted on a conventional injection molding machine. Characterization of the powder and binder feedstock is conducted to enable the selection of suitable processing parameters. The injection molding of 316L stainless steel microstructures and the problems encountered are addressed in this paper. Study shows that microstructures of 100 mum diameter and height of about 200 mum can be produced by muPIM, but there are still problems to overcome.