Objective: The aim was to investigate indicators related to DNA damage and cancer pathogenesis in Type II diabetes cases with breast cancer. It was planned to evaluate the relationship between these markers with oral antidiabetic drugs. Research Design and Methods: Fourty patients and 10 healthy individuals were included in the study. HIF-$1{alpha}$ and 8-OHdG are examined in blood samples taken from these individuals with an ELISA Kit. Statistical analysis of data was performed with 95% confidence using Windows package program SPSS 15.0. Results: HIF-$1{alpha}$ parameters were found to be meaningfully higher in the patient group than the controls in both pretreatment and posttreatment periods (p<0.05). No significant differences in terms of 8-OHdG between patients and controls. However, posttreatment serum HIF-$1{alpha}$ ve 8-OHdG levels was found lower than pretreatment levels in patients receiving metformin, but not with pioglitazone. Conversely, serum 8-OHdG levels decreased significantly in these patients. When patients were evaluated according to the treatment groups (pioglitazone vs. metfformin) no significant differences in terms of serum HIF-$1{alpha}$ and 8-OHdG levels between treatment groups. Conclusions: HIF-$1{alpha}$ levels decreased significantly in the patient group receiving metformin. However, there was no significant difference in terms of HIF-$1{alpha}$ levels in the patients receiving pioglitazone.