Significant advances have occurred in the diagnosis, treatment, and long-term outcome of patients with acute promyelocytic leukemia (APL). The purpose of this review is to describe the molecular genetics of this disease, the use of all-trans retinoic acid (ATRA) in clinical trials of APL, and the clinical and basic research questions for future investigation. Findings of clinical studies in mainland China using ATRA as induction therapy for patients with APL concurrent with laboratory characterization of the molecular changes in APL have led to worldwide clinical trials of ATRA in the treatment of patients with APL. Major advances in understanding the molecular biology and genetics of APL have occurred over the past 5 years. These findings have been translated into novel treatment strategies using all-trans retinoic acid as a differentiation agent in the induction phase of therapy resulting in improved long-term outcome, reduced morbidity, and lower costs for patients with APL. Advanced molecular techniques are being employed for diagnosis and for monitoring of patient response to treatment.