This study was aimed to search the effect of Sodium Fluoride (NaF) and 7,12 dimethylbenz(a)anthracene (DMBA) to erythrocyte fragility and parameters in rats. The nine groups were formed and each group contained 8 animals. Group 1: Control group (without any treatment). Group 2: Sesame oil (vehicle for DMBA). Group 3: 1 ppm NaF. Group 4: 15 ppm NaF. Group 5: 30 ppm NaF. Group 6: DMBA.Group 7: 1 ppm NaF + DMBA. Group 8: 15 ppm NaF + DMBA. Group 9: 30 ppm NaF + DMBA. Fluoride was added into the animals' drinking water in the form of NaF once a day, for 12 weeks. DMBA (10 mg/kg) was administered once a week and in a total of 12 weeks with oral gavage. Erythrocyte fragility was analyzed with osmotic hemolysis method and erythrocyte parameters with blood cell counter in whole blood. At 0.4% NaCl concentration groups 4, 5, 6, 8, and 9 showed significantly higher erythrocyte fragility values than control group (p <= 0.05). At 0.5% NaCl concentration, groups 6, 8 and 9 showed significant increase in erythrocyte fragility compared to other groups (p <= 0.05). The erythrocyte and hematocrit values were found significantly high in group 5 (p<0.001) and group 4 (p<0.01) while it was found low in all groups with DMBA (6, 7, 8, 9) (p <= 0.05) compared to control group. Hemoglobin amount in group 5(p <= 0.01) and group 4 (p <= 0.05) were significantly higher than other groups. MCV and MCH in group 5 were significantly lower and these values in all groups with DMBA (6, 7, 8, 9) were determined significantly high compared to other groups. RDWC in group 5 (p <= 0.001) and group 4 (p <= 0.01) and in all groups with DMBA (6, 7, 8, 9) (p <= 0.05) was significantly increased compared to other groups. As a result, exposure to high doses of floride and DMBA may cause augmented erythrocyte fragility, abnormal erythrocyte parameters and anemia. Therefore, measures must be taken to protect the health of all living organisms in area exposed to high levels of fluoride and DMBA.