Blends of a polypropylene matrix and a miscible phase of ethylene vinyl acetate and ethylene methyl acrylate copolymers were produced by twin-screw extrusion. The miscible phase can be crosslinked in, situ through a catalyzed transesterification reaction. Mechanical properties of reactive and nonreactive blends were characterized. Impact properties increase with the concentration of elastomeric phase and are improved by the crosslinking reaction. Yield stress and Young modulus are not modified by the reaction, but tensile stress and elongation at break are improved, which suggests the development of network structure at the interface.