Abstract: The present invention relates to a method of preparing magnetic oocytes and/or embryos by means of nanoparticles for assisted reproduction techniques and to the use in assisted reproduction techniques of non-human oocytes and/or embryos prepared with said method. Said method comprises: a step in which magnetic nanoparticles are conjugated with oviduct recombinant protein, OVGP1r; a step in which it is verified that the nanoparticle-OVGP1r conjugation attaches to the ZP of oocytes/embryos after being incubated together; and a step in which the number of oocytes/embryos having nanoparticles attached to them distributed around the ZP without being endocytosed is verified; and it is assessed if the amount of magnetic nanoparticles attached to the ZP of oocytes/embryos is enough to be attracted by a magnetic field.