Epigenetic changes, including DNA methylation, influence the structure of chromatin, gene expression and genomic stability. It appears that the abnormal pattern of DNA methylation may be important in pathological conditions, including colorectal cancer. The most common pathway leading to this tumor is adenoma-carcinoma sequence. It was reported that during this process changes in the pattern of DNA methylation occurred, but the question whether these changes are the causes of neoplastic transformation of colorectal cancer or the consequences of pathological changes in the cancer cells is still open. Thus, changes in DNA methylation pattern may influence the pathogenesis of colorectal cancer but this hypothesis has not been confirmed experimentally and there is a need for research determining the relationship between changes in DNA methylation profile and colorectal cancer. By analyzing methylation of DNA sequences a molecular subgroup of this tumor has been distinguished. It is characterized by a high frequency of methylation of genes and it was denoted CpG islands methylator phenotype (CIMP). Changes in the pattern of DNA methylation are used as molecular markers for diagnosis and screening of colorectal cancer. A better understanding of changes in DNA methylation in colorectal cancer may help to facilitate prognosis and prediction of the disease and to improve its diagnosis.