Using inexpensive and nontoxic metal salt (FeSO 4 ·7H 2 O) as a reactant, γ-Fe 2 O 3 (maghemite) nanoparticles with crystallite size around 80 nm have been synthesized in an aqueous medium by low power, low temperature and simple sonochemical method. XRD, Rietveld refinement and Williamson-Hall method was employed for understanding the structure of the synthesized sample. FTIR spectra were recorded for studying the presence of organics. MT measurement performed at 500 Oe showed that the sample exhibit a magnetization of about 34 emu/g at 300K and hence can be used for magnetic hyperthermia treatment (MHT). Calorimetric studies performed showed an improvement in temperature up to 12 °C with a minimum time of 210s. Specific absorption rate calculation showed that sample with minimum concentration is better for MHT.