The peripheral T-cell lymphomas are a rare and heterogeneous group of mature T-cell lymphomas with limited available therapies. The outcome of frontline chemotherapy regimens has been disappointing, with a long-term survival of only 20%-30%. There is an urgent need to optimize induction therapy by incorporating novel agents that target the dysregulated pathways. Histone deacetylase inhibitors that induce acetylation of histones and enhance apoptosis have shown promising activity. In this article, we summarize the role of histone deacetylase inhibitors and specifically discuss pharmacokinetics, efficacy, and toxicity of the recently US Food and Drug Administration-approved agent belinostat for its use in patients with relapsed/refractory peripheral T-cell lymphoma.