BiFeO₃ is a multiferroic material that attracts attentions of many research groups due to its potential as being ferroelectric and ferromagnetic above room temperature. We have prepared both undoped- and Mn-doped BiFeO₃ by sol-gel auto-ignition method. Doping of Mn has resulted in decreasing grain size from 60 to 32 nm. X-ray diffraction data show that the samples are pure and single-phase. Infrared measurements on BiFeO3 and Mn-doped BiFeO₃ revealed intrinsic stretching vibrations of tetrahedral sites of Fe³⁺ -O and of octahedral Bi³⁺- O as well. On the other hand, as the Mn concentration increases, the magnetic moment of BiFeO₃ increases. It gives some suggestions in manipulating structural and magnetic properties of BiFeO₃ by doping Mn.