Cancer cells are characterized by epigenetic dysregulation, including global genome hypomethylation, regional hypo- and hypermethylation, histone modifications, and disturbed genomic imprinting. These alterations can be used as markers in cancer epidemiology to assess risk as well as follow-up of the disease. Some of the methylation markers can be assayed on microarray chips on which a very small amount of sample is needed, and the assays are robust and the markers have high specificity and sensitivity. Implication of epigenetic markers in cancer detection, diagnosis, prognosis, control, and cancer epidemiology is discussed.