Dasatinib, an effective second-generation tyrosine kinase inhibitor, is used to treat breakpoint cluster region-Ableson-positive chronic myeloid leukemia or Philadelphia chromosome-positive acute lymphocytic leukemia. One common adverse event associated with dasatinib use is fluid retention, including pleural effusion. Chylothorax, however, is a rare adverse event. Although the precise mechanism of dasatinib-induced chylothorax is unclear, almost all cases involve right or bilateral chylothorax, and mostly occur within 5 years of dasatinib initiation. Here, we report a rare case of a patient with dasatinib-induced massive left chylothorax 10 years after dasatinib initiation, which improved after dasatinib termination and a switch to bosutinib.