Maghemite (γ-Fe2O3) nanoparticles were synthesised using the co-precipitation method, with different concentrations (5 M, 10 M, 11 M, 12 M and 13.4 M) of sodium hydroxide (NaOH) as the precipitation agent. The resulting powder was characterised using x-ray diffraction (XRD), vibrating sample magnetometer (VSM), and transmission electron microscope (TEM). All characterisations were performed at room temperature. The XRD results showed that the γ-Fe2O3 powder was in a single phase for samples synthesised using 11 M, 12 M and 13.4 M NaOH and the crystallite size ranged between 5.74 nm–6.42 nm. TEM observations and analysis showed that the particles were in a cubo-spheroidal shape and the mean physical size of the nanoparticles was between 8.52 nm and 8.59 nm. Hysteresis loop indicated that γ-Fe2O3 nanoparticles have superparamagnetic properties with an acceptable range of saturation magnetisation of 31.08 emu/g–48.88 emu/g and negligible coercivity value. MTT assay demonstrated that the γ-Fe2O3 nanoparticles exhibited biocompatibility with V79-4 cells at different dosages (1000 μg/mL–50 μg/mL) for 48 h. The results suggested that maghemite can be a valuable low-cost biomagnetic material in biomedical applications.