The paper presents structure and properties of high-speed steels made using the Metal Injection Molding method and heat treated. It has been demonstrated that the experimental steels of the HS6-5-2 and HS12-1-5-5 types manufactured with the MIM method should be austenitized at lower temperatures, compared with the same steel grade produced using other powder metallurgy methods or conventional ones. A higher carbon concentration in these steels, resulting from the binder degradation process causes lowering of the solidus temperature, and consequently, of the sintering and austenitizing temperatures of these steels. Moreover, a higher carbon concentration causes increase of the retained austenite portion and lower hardness after quenching.