All-trans-retinoic acid (ATRA) has been successfully used in the treatment of acute promyelocytic leukemia (APL). One of its adverse effects is acute pancreatitis. In the literature, a proposed cause of acute pancreatitis is hypertriglyceridemia. Here, we present the case of a 45-year-old male with APL, treated with ATRA combined with induction chemotherapy (cytarabine and idarubicin), who developed acute pancreatitis without overt hypertriglyceridemia. This finding suggests that hypertriglyceridemia might not be the sole contributing factor in the pathogenesis of ATRA-induced acute pancreatitis and that attention should be paid to the possibility that ATRA treatment causes acute pancreatitis in the absence of overt hypertriglyceridemia.