A new synthetic method for the formation of uniform α-Fe₂O₃ nanoparticles was reported and their magnetic properties were investigated. The sonochemical synthesis and the subsequent take-off technique resulted in spherical shaped α-Fe₂O₃ nanoparticles with an average diameter of 60 nm. The temperature- and applied magnetic field-dependent magnetization of the α-Fe₂O₃ nanoparticles was explained by the sum of two contributions, i.e., the Morin transition and superparamagnetism, because the critical size for superparamagnetism was within the size variation of the nanoparticles.