Background: Ionizing radiation irradiated from iodine-131 can induce DNA damage and cell death. The cellular DNA damage is the cause of mutation and cancer. The micronucleus assay in polychromatic erythrocytes was applied to assess the radio-protective effect of Turmeric extract on genotoxic potential of iodine therapy. Materials and Methods: Thirty six male albino rats were randomly divided in six groups. A single dose (200 or 500 mg/kg) of Turmeric extract was injected to the rats 30 min before iodine therapy. Iodine-131 (5.55 MBq) was administrated intra peritoneal to the experimental animals. The percentage of micronuclei in PCE, NCE and ratio of PCE / (PCE + NCE) was determined 48 h after iodine injection for each experimental group to assess iodine-131 radiation effects with or without Turmeric extract. Results: Iodine therapy showed a significant increase in the number of micronucleus formation. The animals treated with different doses of Turmeric extract + iodine showed a significant reduction in the frequency of micronucleus compared to the animals treated with iodine-131 alone. Both doses of Turmeric extract had the same effect when injected 30 min prior to iodine therapy. Conclusion: Our results indicate protective effect of Turmeric extract against genetic damages induced by iodine-131 administration.