In the course of this research, the effect of two polymers (xanthan gum and polyanionic cellulose) on the rheological properties of KCl/polymer type drilling fluids was investigated. Non-Newtonian drilling fluids are conventionally characterized by rheological models (Bingham Plastic, Power Law, Casson, Herchel-Bulkley and Robertson-Stiff). In this research, forty-five KCl/polymer data sets of varying compositions are prepared. Polymer addition to the system has affected the model and caused a variation of Power Law Model parameters, consistency index and flow behavior index. Consistency index was observed to increase as the polymer concentration increased, supplying more shear stress values. Decrease of flow behavior index due to polymer addition is interpreted as deviating from Newtonian behavior Gelation for both 10 s and 10 min has increased by polymer addition to the system.