Traditional treatments for cancer include chemotherapy, radiation therapy, and surgery. Recently, epigenetic inhibitors have been found to be very effective in cancer treatment. Epigenetic changes such as DNA methylation, histone deacetylation, and microRNA (miRNA) expression are capable of silencing the expression of tumor suppressor genes and inducing oncogenes, leading to clonal proliferation of tumor cells. Methyltransferase inhibitors and histone deacetylase inhibitors have attracted the attention of researchers and clinicians because they provide an alternative therapeutic regime in some diseases, including cancer.Epigenetic changes are characterized by altered gene expression without any changes in the nucleotide sequences of DNA. In addition, epigenetic changes are dynamic and can be reversed by epigenetic inhibitors. Drugs that inhibit DNA methylation or histone deacetylation have been studied for the reactivation of tumor suppressor genes and repression of cancer cell growth. Epigenetic inhibitors work alone or in combination with other therapeutic agents. To date, several epigenetic inhibitors have been approved for cancer treatment. The main challenge in the field of epigenetic inhibitors is their lack of specificity. Their mechanisms of action and potential in treating cancer are described in this article.