The mature T and NK cell lymphomas are rare, comprising approximately 10% of all malignant lymphomas. The incidence of T-cell lymphoma is variable around the world, with a higher incidence compared to B-cell lymphomas in the Asian basin. While the overall incidence of B-cell lymphomas has begun to decline in the United States, the incidence of T-cell lymphomas continues to rise. Over the last decade, a number of novel agents have been developed which target T-cell lymphomas and studies have identified novel genes and pathways associated with lymphomagenesis in T-cells.