All trans-retinoic acid (ATRA) is a targeted therapy, used in Acute Promyelcytic leukemia (APL) and causes the abnormal promyelocytes to differentiate in to mature leucocytes, however their clearance in vivo is not known. ATRA has been found to be associated with hemophagocytosis, but sometimes one may find phagocytosis of differentiated cells by histiocytes without the overt manifestations of hemophagocytic syndrome. We report a case of APL showing differentiated cells being phagocytosed by marrow histiocytes while patient was getting ATRA therapy.