Background: Inherent radiosensitivity associated with elevated chromosomal aberrations (CA) was shown in breast cancer (BC) patients at cellular level. Different agents were used to protect cells against adverse effects of ionizing radiation (IR), mainly antioxidants such as vitamins. The aim of this study was to evaluate the modulating effect of saffron extract on radiation induced CA in lymphocytes of normal individuals and BC patients. Materials and Methods: G₂ assay was applied on whole peripheral blood lymphocytes received from 5 normal controls and 10 BC patients with luminal A subtype. Blood culture was initiated in complete culture medium, 4h prior to harvesting cells were irradiated with 1 and 2 Gy X-rays. Pretreatment of samples with saffron was done 2 h before irradiation. After metaphase preparation and slide making, slides were stained in Giemsa. Hundred well spread metaphases were scored for presence of chromatid type aberrations with a microscope at a magnification of 1000×. Result: Results indicated a high and significant frequency of CA both in lymphocytes of normal and BC patient after irradiation. Pretreatment of samples with saffron led to a significant increase in the frequency of breaks in lymphocytes of both normal individuals and BC patients. Conclusion: Results indicate that despite its antioxidant property, pretreatment of lymphocytes of normal individuals and BC patients with saffron before X-irradiation led to radiosentisizing effect. The way saffron sensitize lymphocytes to X-rays is not known, but it might be possible to inhibit repair of radiation induced DNA strand breaks.