The synthesis and characterization of polycrystalline room-temperature ferromagnetic semiconductor (In0.9Fe0.1–xMnx)2O3 (x=0–0.1) oxide are reported. All of the samples with intermediate x values are ferromagnetic at room temperature. The highest saturation magnetization moment at 300 K per total amount of magnetic ion is reached in the (In0.9Fe0.04Mn0.06)2O3 sample. The lattice constant a increases linearly with increasing Mn content. Fe-only doped samples were paramagnetic, while a Mn-only doped sample was found to be ferromagnetic below TC=46 K.