This paper presents the rheology and morphology of immiscible polymer blends compatibilized by a polymer reaction at the interface. Nylon-6 was melt blended in a twin screw extruder with several different grades of maleated polypropylene at 10 and 20 wt%. The extent of polymer reaction at the interface is varied by varying the extent of maleation of polypropylene and affects the phase morphology differently at different phase volume fractions. The rheology of the reactive blends is fit to the Palierne theory to infer values of the equilibrium interfacial tension. The equilibrium intel facial tension of the reactive blends is reduced in proportion to the extent of maleation of the polypropylene. In blends with more reaction product, another mechanical property of the interface is required to fit the low-frequency data well.