Chronic myeloid leukemia (CML) is a chronic myeloproliferative disease almost always caused by a genetic defect known as the Philadelphia (Ph+) chromosome. Ph+ chromosome is associated with a BCR/ABL fusion gene expressed as an oncoprotein, which is generally considered as the initiator for the chronic phase of CML. Tyrosine kinase inhibitors (TKI) are target-specific therapeutic agents that achieves successful complete responses rates for majority of CML patients. However, blastic crisis BC of CML is still a great therapeutic challenge even in the TKI era. Dasatinib is the most effective TKI for blastic phase CML, but tumor burden is very high for terminal stage of advanced CML disease. In this report, tumor lysis syndrome (TLS) with acute renal failure occurring after the dasatinib treatment initiation in BC-CML was presented. Dasatinib is effective in BC of CML and tumor lysis syndrome due to TKI effect should be taken into account during initial treatment of patients with high tumor load.