A case of acute promyelocytic leukemia (APL) treated with all-trans retinoic acid (ATRA) is reported. After the diagnosis was established, the patient was given oral ATRA (30 mg/d) in combination with small dose of hydroxyurea, platelet concentrates, and fresh frozen plasma etc. From day 19 after ATRA administration, successive thromboembolic events occurred. In spite of the partial remission on day 32, the patient died of cardiopulmonary insufficiency. Our experience from this case suggests that more attention should be given to thromboembolic events during ATRA therapy, and the use of active anti-coagulant may prove beneficial when signs of hypercoagulation are present in APL patients.