Arsenic trioxide has recently been reported to be successful in the treatment of promyelocytic leukemia. Several concerns about the use of this toxic agent are currently reducing its potential clinical use even in severely ill patients. In this report we describe the results achieved by As2O3 with all-trans retinoic acid in a patient suffering from secondary, relapsed, resistant promyelocytic leukemia. Several complications, including sepsis and an extensive area of skin necrosis, did not allow us to treat the patient further with chemotherapy. With As2O3 and ATRA therapy, the patient obtained a complete molecular remission without any significant toxicity and, subsequently, it was possible to perform a bone marrow autograft in a state of complete remission.