Colorectal cancer is the third most common cancer worldwide and arises secondary to the progressive accumulation of genetic and epigenetic alterations in normal colon cells, which results in a polyp-to-cancer progression sequence. It is known that individuals with a personal history of colon adenomas or cancer are at increased risk for metachronous colon neoplasms. One explanation for this increased risk could be field cancerization, which is a phenomenon in which the histologically normal tissue in an organ is primed to undergo transformation. Epigenetic alterations appear to be promising markers for field cancerization. In this review, we discuss field cancerization in the colon and the data supporting the use of methylated DNA as a biomarker for this phenomenon.