The contribution of epigenetic changes in triggering breast cancer initiation, promotion, progression and metastasis is an established fact. Altered expression profiling of several genes on DNA is also influenced by histone modifications. In this review, the role of those enzymes regulating histone modifications is discussed. These enzymes are termed as histone acetyltransferases (HATs) and histone deacetylases (HDACs). Understanding of mode of action of these enzymes will be helpful in exploring their antagonistic role on histone-DNA complex. In addition to this, the significance of potential histone deacetylases inhibitors (HDIs) as potential cancer therapeutic marker is also discussed.