Interfacial tension (IFT) reduction is widely acknowledged as one of the prominent oil recovery mechanism during nanofluid flooding enhanced oil recovery (EOR). Hence, in this work, an investigation of IFT at the crude oil-nanofluids interfaces was carried out using the Wilhelmy plate method in the presence of electromagnetic (EM) field. EM wave propagation within sandstone saturated with oil and nanofluids were simulated using COMSOL Multiphysics solver. A dielectric (ZnO) and magnetic (Fe2O3) nanoparticles were synthesized, and their EM properties as well as IFT reduction ability were measured. The superior EM properties of Fe2O3 nanoparticle contribute to its maximum IFT reduction of 6.13 of the crude oil-nanofluid interface under EM wave. The presence of Fe2O3 nanoparticles in sandstone saturated with oil and Fe2O3 nanofluid increases the sandstone response to EM wave. This is shown by reflection loss peak of �19.9 dB, equivalent to approximately 99 absorption of the EM wave at 1 GHz, with a matched impedance of 46.5 Ω. Hence, EM-assisted nanofluid flooding experiment conducted with bespoke core flooding system shows that oil recovery increased by 13.6 over the case without EM propagation during Fe2O3 nanoflooding. This could be attributed to increased fluid mobility in the sandstone due to IFT alteration and high EM response of the sandstone core. This result shows the potential application of magnetic nanofluid coupled with EM wave for enhanced oil recovery. © 2020 Elsevier B.V.