Nanocrystalline Bi1-x Mnx FeO3 (0 ≤ x ≤ 0.3) materials were synthesized using sol-gel technique. The structural and magnetic properties were investigated in detail. Rietveld analysis from XRD revealed the structural formation of BiFeO3. As the Mn doping concentration was increased, the structure of BiFeO3 changed from rhombohedral to tetragonal. All the M-H loops showed the ferromagnetic behavior in the prepared samples. Magnetization was observed to enhance as the Mn doping concentration was increased. The enhanced magnetization may be due to the collapse of the space modulated spin structure as observed from the structural changes. © 2016 V. Srinivas et al.