Dasatinib, a second-generation BCR-ABL tyrosine kinase inhibitor (TKI), is administered to patients with chronic myeloid leukemia (CML) or Philadelphia chromosome-positive acute lymphoblastic leukemia. However, it occasionally induces pleural effusion. There are only a few reports about pathological findings on pleural biopsy, and the underlying mechanism has not yet been elucidated. A 66 year-old man with CML developed right pleural effusion after dasatinib treatment for 2 years and 8 months. Lymphocyte-predominant exudative pleural effusion was identified. Thoracentesis and diuretics exhibited poor therapeutic effects; thus, dasatinib was switched to bosutinib. Pleural biopsy using local anesthetic thoracoscopy was performed to eliminate the possibility of infectious diseases or malignant mesothelioma. Pathologically, the dasatinib-induced pleural effusion demonstrated nonspecific pleuritis with infiltration of various inflammatory cells, such as lymphocytes and myeloid cells, in the pleural tissue. Our findings indicate the involvement of an immune-mediated mechanism in the onset of dasatinib-induced pleural effusion and the usefulness of local anesthetic thoracoscopy.