Uniformly sized α-Fe 2 O 3 hexagonal platelets were synthesized by a hydrothermal process using Fe(OH) 3 suspension and large amount of NaOH. The reaction products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and a vibrating sample magnetometer (VSM). The results show that the hexagonal platelets are fine, monodisperse and consisting of single-crystals. The magnetic hysteresis (M–H) curve of the samples measured at room temperature indicates that the α-Fe 2 O 3 micro-platelets exhibit ferromagnetic behaviors with relatively low coercivity.