Gamma radiation produces numerous biological perturbations in cells by direct ionization of DNA and cellular targets and by indirect effect through damage by free radical production. The present study has been carried out to investigate the possible therapeutic effect of folic acid loaded magnetic nanoparticles through injection after whole body gamma irradiation. Results showed that whole body gamma irradiation of rats at 6Gy (single dose) induced significant increase in DNA damage (P < 0.05) that was indicated by increase in tail length, tail DNA% and tail moment as compared to control group. And significant increase in the hepatic cholesterol and triglycerides levels was observed after three weeks post-irradiation. Administration of folic acid loaded magnetic iron oxide (Fe3O4) after irradiation induced significant improvement of the DNA damage and hepatic cholesterol and triglyceride level. These results indicate the possible role of folic acid loaded MNPs as a therapeutic agent against the genetic damage caused by ionizing radiation.