In this work, the sintering of a Hadfield steel (Fe-12Mn-1C-1Si) produced by MIM was investigated through dilatometry and microstructural characterization. The feedstock was prepared by mixing carbonyl iron, graphite, ferromanganese and ferrosilicon powders. Samples were injection molded and the debinding occurred in a two-fold route, solvent immersion and plasma debinding. The brown parts were sintered in the dilatometer to evaluate the dimensional changes of the samples during heating, isothermal holding and cooling. The influence of alloying powders, sintering temperature and gas atmosphere was investigated experimentally. The desired austenitic microstructure was obtained after sintering, however presenting precipitates at the grain boundaries, associated to the low cooling rate applied. Furthermore, the use of coarse FeMn powder (~45 µm) generated large secondary pores, which were not minimized by higher sintering temperature. Nevertheless, it was seen that oxidation may be minimized by changing the chemical potential of oxygen in the atmosphere, e.g. by using oxygen getters.