The melt blending of polycarbonate (PC) and ethylene-methacrylic acid copolymers (EFC) either in the acid form (EFC-H) or partially neutralized with sodium (EFC-Na) or zinc (EFC-Zn) was investigated. Torque monitoring of the blending showed that the polymers are capable of reacting generating new chemical species that increase the melt viscosity. As general behavior, the torque curves pass by a maximum that takes place before 30 min, the final torque being higher than that of the individual polymers. SEC analyses reveal that PC degradation also occurs and is stronger in the case of blends with EFC-Na that acts to catalyze PC degradation, promoting CO, formation. FTIR studies on chloroform insoluble fractions of the PC/EFC-Zn blends showed that in addition to a very small number of carbonate groups, feature absorption bands of aromatic ester and hydroxyl groups appear in the new chemical species formed during the reactive processing.