 Chemotherapy resistance, either innate or acquired requires for its development, expression changes on a large number of genes therefore, it has been hypothesized that epigenetic-mediated changes could be the responsible driving force for chemotherapy resistance. Aberrant DNA methylation and histone deacetylation are the main epigenetic alterations hence, their reversal by inhibitors of DNA methylation and histone deacetylases HDACs may overcome resistance in refractory solid tumors. 