The bending strength of sintered ferrites has been studied for MgCuZn-, NiCuZn-, and MnZn-ferrites. It has been found that residual carbon content affects bending strength of these sintered ferrites. The sintered ferrites containing much residual carbon lower the bending strength. It is considered that PVA, which is added when the ferrite powder is granulated, remains as residual carbon in sintered ferrite after sintering. Control of the residual carbon content of sintered ferrite is one of the most important factors for obtaining high performance ferrite.