We report the multi-gram production of water-dispersible superparamagnetic iron oxide nanoparticles (SPIONs) by microwave-assisted reaction. A laboratory-scale reaction performed in a single-mode microwave unit (4.5 mL, producing 22 mg of Fe2O3) was scaled-up in a multi-mode equipment (up to 500 mL, corresponding to 2.61 g Fe2O3). The quality of the final material in terms of size, colloidal stability and magnetic properties, and the yield of the reaction (similar to 80%) were not compromised in the large-scale setup. Hence, these results reinforce the potential of microwave irradiation in industrial laboratories to synthesize high quality nanoparticles readily dispersible in water and in a short time. (C) 2015 Elsevier B.V. All rights reserved.