Abstract: Bruton′s tyrosine kinase(BTK), a crucial terminal kinase enzyme in the B-cell antigen receptor(BCR)signaling pathway, has emerged as an attractive target for therapeutic intervention in human malignancies and autoimmune disorders. A number of BTK inhibitors have progressed through advanced preclinical development to clinical trials. Among them, ibrutinib(PCI-32765, brand name: Imbruvica)demonstrated high clinical activity in B-cell malignancies, especially in patients with chronic lymphocytic leukemia(CLL), mantle cell lymphoma(MCL), and was recently approved by the U. S. Food and Drug Administration. In this paper, the structure and function of BTK are reviewed; preclinical and clinical development of ibrutinib and other novel BTK inhibitors are summarized.