Water-dispersible Fe-Au alloy nanoparticles (FA_NPs) for hyperthermia application were synthesized and characterized in this study. From transmission electron microscopy examination, the mean diameter of the FA_NPs was calculated to be 3.9 ± 1.3 nm. The X-ray powder diffraction pattern of prepared FA_NPs shows 2θ peak positions corresponding to pure iron and gold. X-ray fluorescence analysis results show that the FA_NPs were composed of 36.8 wt% iron and 63.2 wt% gold, corresponding to a molecular ratio of iron to gold of 2. Electron spectroscopy for chemical analysis was used to study the binding energies of the atoms. To examine the magnetic properties, superconducting quantum interference device tests were conducted, and field-cooled and zero-field-cooled curves were obtained. The results reveal that the FA_NPs were superparamagnetic at room temperature with a saturation magnetization of 3.5 emu/g. The zeta potential was measured to be -29.8 mV for FA_NPs suspended in deionized water, which indicates good suspension. The in vitro cytotoxicity of the FA_NPs was evaluated using L929 and Hep- G2 cell lines through the WST-8 assay. No significant cytotoxic response was observed for either cell line for concentrations below 10 mg/mL after 24 h of cultivation. Hyperthermia evaluations were carried out with a 1.1-MHz high-frequency induction wave (HFIW) exposure. Each FA_NP was calculated to provide 1.33 × 10-16 J of heat. The viability of the Hep-G2 cell decreased under hyperthermia treatment. The FA_NPs prepared in this study have potential for hyperthermia application.