Unsteady state two-phase flow experiments were performed to check the action of an adsorbed water-soluble polymer on relative permeability and capillary pressure. A selective reduction of the relative permeability to water with respect to relative permeability to oil was observed. Capillary pressure, measured directly on the core, was increased after polymer injection. Since the polymer has little influence on interfacial tension, this trend is interpreted as a reduction of pore size due to polymer adsorption. The validity of this assumption was checked by the investigation of a pore-scale numerical model. Relative permeabilities and capillary pressure were computed for a range of flow rates. Numerical results indicated that the polymer adsorption model (wall effect) successfully reproduces qualitatively the experimental observations.