We examine whether the level of 8-oxo-2 -deoxyguanosine (8-oxodGuo) in lymphocytes DNA is higher in colon cancer when compared to the control group. Factors that may influence oxidative stress such as antioxidant vitamins and uric acid were also determined. Blood samples were obtained from a control group of 55 healthy persons and 43 colon cancers. 8-OxodGuo level and the vitamins concentration were measured by high-performance liquid chromatography. The levels of 8-oxodGuo were significantly higher whereas the concentrations of the vitamins and uric acid were significantly lower in colon cancer patients than in control group. Therefore, the decreased concentration of antioxidant vitamins together with lower amount of uric acid may be responsible for the formation of pro-oxidative environment in blood of colorectal carcinoma patients.