Co-delivery approach has been recommended to reduce the amount of each drug and to achieve the synergistic effect for cancer treatment. Curcumin (CUR) and sulforaphane (SF) have antitumor effects, but their application is limited because of their low water solubility and poor oral bioavailability. To improve the bioavailability and solubility of SF and CUR, we performed an innovative co-delivery of them with PEGylated gold coated FeO magnetic nanoparticles (PEGylated FeO@Au NPs) to endorse SF and CUR maintenance as an effective and promising antitumor drugs. The structure of the synthesized nanocarriers evaluated by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometer, dynamic light scattering and Fourier transform infrared spectroscopy. The results revealed that the zeta potential of CUR and SF-loaded NPs were about -15.4 mV and the average sizes were 80.57 nm. They were monodispersed (polydispersity index = 0.161 ± 0.016) in water with high drug-loading capacity and stability. CUR and SF were encapsulated into NPs with loading capacity of 17.32 ± 0.023% and 16.74 ± 0.015% and the entrapment efficiency of 83.72 ± 0.14% and 81.20 ± 0.18% respectively. The study of SF and CUR loaded PEGylated FeO@Au NPs on human breast adenocarcinoma cell line (MCF-7) confirmed that cytotoxicity of SF and CUR can enhance when they are loaded on PEGylated FeO@Au NPs in comparison to free SF and CUR. The results of real-time PCR and flow cytometry shown that this combination can increase therapeutic effects of SF and CUR by apoptosis and necrosis induction as well as inhibiting of migration in MCF-7 cell line.