Powder injection molding (PIM) is a multi-stage process to manufacture metallic or ceramic complex, functional parts in large quantities and with high material requirements. The flow in PIM filling process is a complicated problem with viscoelasticity effect, instability and non-isotherm. The exactly describing of whole process of the flow is very difficult. The existence of a yield stress on PIM-feedstock depends on particle interactions within polymer matrix. Further, factors, like powder loading and dispersion during the measurements influencing the rheological characterization of PIM-feedstocks. Additionally, inertial and gravitational effect can have an influence at system with very low viscous matrix. Quantifying yield stress, however, must be done carefully because the value obtained depends on the analytical technique used. Knowing of the flow behavior of PIM-feedstock is necessary for successful filling simulation of PIM. In this context, the yield behavior of a stainless steel feedstock was studied using a plate and plate controlled stress rheometer (CSS). The rheological data obtained from CSS were compared to the measurement made on a slit-die rheometer in controlled shear rate mode (CSR). Controlled stress rheology is more sensitive and provides more accurate results of yield stress than CSR. Keywords: powder injection molding, stainless steel feedstock, yield stress