A 40-year-old Asian male who presented with leukocytosis was diagnosed with chronic phase chronic myeloid leukemia. Cytogenetic karyotyping analysis showed 46,XY,t(4;9;22)(q21;q34;q11.2). He was treated with bosutinib and then changed to dasatinib because of intolerance, and MR4.5 (BCR-ABL/ABL ≦ 0.0032%, international scale) was achieved after 17 months of continuous treatment...the first successful case treated with tyrosine kinase inhibitors in the world.