Materials of 79 patients who were examined and treated with the diagnosis of colorectal cancer and adenomatous polyps at the Oncology Clinic of Azerbaijan Medical University were included in the present study; the control group consisted of 14 healthy adults. The age of the patients varied between 36-65, 58 of them were men, and 21 were women. 10 of the healthy persons were female, and four were male. The concentration of calprotectin and cathelicidin in blood serum was carried out by immunoenzymatic method. The principle of the method is based on the use of specific antibodies against the peptide sequence of the studied antimicrobial peptides. In the research work, it is determined that the concentration of cathelicidin in the blood serum of group I patients is higher than the control limits in all patients. Hence, its concentration increases statistically reliably by 2.2 times compared to the control. The reliability coefficient of the difference is calculated as p<0.001. Its average statistical value is 2.10 ± 0.09 pg/ml. The group's minimum value is 1.3 pg/ml, and the maximum value is 2.8 pg/ml.