Curcumin-loaded hybrid magnetic nanoparticles (HMNPs) were formulated using a simple and green method. At first, surface of FeO nanoparticles was modified using alginate (ALG), and magnetic ALG/FeO nanoparticles with a size of 33 nm and a zeta potential of -25 mv were prepared. Then, a complex including bovine serum albumin (BSA) and poly((3-acrylamidopropyl)trimethylammonium chloride) (p(APTMACl)) was prepared and optimized. The behavior of the BSA/p(APTMACl) complex was evaluated as a function of pH and protein/polymer ratio by UV-Vis spectroscopy, zeta potential, and DLS analysis. Finally, the hybrid complex of BSA/p(APTMACl)@ALG/FeO were prepared using mixing of the BSA/p(APTMACl) and ALG/FeO systems with opposite charges via electrostatic interactions. The prepared BSA/p(APTMACl) @ALG/FeO complex was named hybrid magnetic nanoparticles (HMNPs) and characterized by UV-Vis spectroscopy, SEM, FT-IR, TGA, XRD, VSM, and AFM. Three samples including pure FeO, ALG/FeO, and the final HMNPs exhibited no cytotoxic effect on MCF-7 breast cancer cell using the MTT assay. MTT assay to test the antitumor activity of bare and encapsulated-curcumin against MCF-7 cells showed BSA/p(APTMACl)@ALG/FeO nanoparticles are able to stabilize the curcumin anti-cancer drug and also enhancing the antitumor activity of the encapsulated curcumin. After loading of curcumin with a high efficiency of 95%. The accumulative release profiles of curcumin were investigated at 37 °C in phosphate buffered saline (PBS, pH 3 and 7.4). The release of curcumin-loaded HMNPs followed the Korsmeyer-Peppas equation and anomalous (non-fickian) diffusion mechanism at pHs 3 and 7.4.