Epidemiological and investigational studies have proved that vitamin D is important in autoimmune processes and has anticancerogenic properties. But the interplay between serum vitamin D and parathyroid hormone (PTH) in colorectal polyps has been less clearly put forward. We evaluated serum vitamin D, PTH levels in Turkish people and tried to stratify colorectal polyps according to risk factors. Patients under-going colonoscopy between January 2012 and March 2012 were c-onsidered to study serum vitamin D levels during winter. Study population comprised of 98 colorectal polyp and 197 normal colonoscopy patients. Results : Serum vitamin D levels were not different between the groups (mean vitamin D level in polyp group 14.3 +/- 11.1 vs. 12.7 +/- 6.74 the normal group, p = 0.12). Likewise serum PTH levels were not different between the groups Patients with polyps were further classified as high and low risk polyps. When discriminant function analysis was conducted, the effects of vitamin D or PTH levels were not again significant. During the study period 16 colorectal carcinoma cases were detected. Serum vitamin D or PTH levels were not significantly different between colorectal cancer or overall study group patients. Finally serum vitamin D levels were stratified into quartiles. Likewise there was not any significant difference between the groups. The present study suggests that serum vitamin D and PTH levels were not different between colorectal polyp and control groups. And serum vitamin D levels were significantly low in both groups suggesting a significant vitamin D deficient state in Turkish patients.