The interfacial diffusion between Ni Zn Cu ferrite and Ag during sintering in the temperature range of 850 950 degrees C was investigated utilizing the scanning electron microscopy-energy-dispersive X-ray analysis technique. It was found that diffusion increased with an increase in the sintering temperature. Furthermore, some impurities in the ferrite powders, especially SiO2 and NH4Cl, promoted the interfacial diffusion. The interfacial diffusion of Ag can be explained by the liquid-phase formation at the grain boundary in the sintered ferrite.