Histone deacetylase inhibitors (HDACIs) are a reassuring group of anti-cancer drugs that alters the gene expression patterns of cancer cells through epigenetic modulation. HDACIs have been reported to intercede with mechanisms along with cell cycle arrest, differentiation, autophagy and apoptosis. They have a vital role in the regulation of tumor cell proliferation. HDACIs have been shown to terminate cell cycle progression at G1 and G2-M phases, reduce chromatin and might also prevent angiogenesis. They have been accepted primarily for use in cutaneous T-cell lymphoma, peripheral T-cell lymphoma, multiple myeloma, acute myeloid leukemia, myelodysplastic syndrome and non-Hodgkin lymphoma.