Acicular shaped γ-Fe 2 O 3 nanoparticles (major axis: 17+/-2nm; minor axis: 1.7+/-1nm) have been prepared using lauric acid as a non-aqueous medium. The products were investigated by IR, TG-DTA, XRD, Raman, SEM, TEM and magnetization measurements. For the preparation of pure γ-Fe 2 O 3 nanoparticles, the suitable condition of the molar ratio of lauric acid to iron nitrate is set 2:1 and the appropriate temperature lies in the range 573-673K. Besides, either pure α-Fe 2 O 3 or a mixture of γ-Fe 2 O 3 and α-Fe 2 O 3 can also be obtained with the change of the molar ratio of lauric acid to iron nitrate. The experimental results indicate that the particle sizes, thermal stability and magnetic properties of the iron oxide strongly depend on the conditions in the preparation.