Even though one is moving towards the success in the discovery of efficient anti-cancer molecules, the drugs used in the treatment of various malignancies are found to possess toxicity and adverse reactivity in the human body that limit their use. The scientists all over the world are engaged in bringing up strategies that aim to develop small molecules that target the abnormal epigenetic factors. The discovery of the role of Histone deacetylases (HDACs) has promised to be a turning point in the treatment of various malignancies. Thus, the invention of potent and safe anticancer therapeutics agents with minimal adverse and side effects are still a major topic of concern and a huge number of research works have been reported in the past few years. This review has been written to discuss on the influence of Histone Deacetylases in cancer malignancies. We have tried to embrace majority of the developments made till date in the field of HDAC and its inhibitors herein. The drugs that are clinically applied, synthesis and SAR study that highlight the chemical groups responsible for evoking the HDAC inhibition and potential of various new classes of HDAC inhibitors (synthetic, hybrid and natural) have also been included.