Background: Colorectal cancers are third most common cancer in both genders. They are associated with genetic and environmental factors. Staging is important in the prognosis. Carcinoembryonic Antigen (CEA) provides preliminary information and there is a correlation between Proliferation Index (PI) and prognostic variables. Our aim is to investigate the relationship between DNA repair capacity and clinico-pathologic factors. Patients and Methods: The blood samples taken from cancer patients were irradiated. DNA repair capacity by comet technique was calculated. The CEA values were recorded. Pathology reports were collected and PI values were calculated. sResults: Total of 30 patients; male (n: 14) and female (n: 16) with a median age of 66.37 10.32 were included. Mean CEA value was 42.85 (1.46 - 422.30 mgr/ml) mgr/ml. Mean % DNA repair capacity was 44.49 5.24. In the pathology; 21 (70%) were T3 tumors; 18 (60%) had lymphatic and 12 (40%) had vascular 2 invasion. Perineural invasion was present in 8 (26.7%). According to the proliferation index (PI); 16 (53.3%) were in high percentile (PI 66%) group. Conclusions: There was a significant correlation between; perineural invasion and tumor grade (P = 0.043); lymphatic and perineural invasion (P = 0.006); lymphatic invasion and vascular invasion (P = 0.034) and the DNA repair capacity with the lymphatic invasion (P = 0.026). There was also a statistically significant (P = 0.044) relationship between PI and lymphatic invasion. As a result in colorectal cancer patients DNA repair capacity can be used as a biomarker in the staging and also in the prediction of the tumor behavior.