Malignant pleural effusion in multiple myeloma (MM) is extremely rare and is associated with poor prognosis. We experienced two cases of MM IgA type with malignant pleural effusion. The diagnoses were based on characteristic cytology and CD138 immunocytochemistry. The patients received several cycles of combination chemotherapy, since symptoms were more aggressive with an uncontrolled pleural effusion. We review the clinical features of these cases and literature concerning myelomatous pleural effusion.