Acute progranulocytic leukemia (APL) is characterized by unique biologic and clinical features. Understanding of these unique features has resulted in dramatic improvements in therapy for patients with APL. Current therapy with all-trans-retinoic acid (ATRA) plus an anthracycline with or without cytosine-arabinoside has yielded complete response rates of 85% or greater and long-term disease-free survival rates of 70% or greater. Arsenic trioxide has also surfaced as an effective induction therapy for relapsed APL. Further progress in the care of patients with APL awaits better definition of optimal schedules for ATRA plus chemotherapy, the role of arsenic trioxide, the use of current molecular monitoring for minimal residual disease, optimal therapy for minimal residual disease, and improved methods to address complications of APL including early hemorrhagic deaths and ATRA toxicities.