Seventeen cases of acute promyelocytic leukemia (APL) treated with all-trans-retinoic acid (ATRA) and combination chemotherapy at Tokyo Metropolitan Komagome Hospital between 1992 and 1999 were reviewed, and divided into 2 karyotype-based cytogenetic groups. One group comprised 7 patients with either the typical t(15;17) alone or a normal karyotype, and the other group comprised 10 patients with additional karyotypic abnormalities. No patient had received prior chemotherapy or irradiation, and no cases were complicated by a history of myelodysplastic syndrome before the diagnosis of APL. There were no significant differences in clinical characteristics at disease presentation. Complete remission was achieved in all 17 patients and karyotypes of bone marrow cells normalized in all cases. No differences were found in relapse rate, overall survival, or disease-free survival between the 2 groups. The analysis did not reveal any significant effect of additional chromosomal abnormalities on the prognosis of APL patients undergoing treatment with ATRA. However, a small number of patients were assessed in this study, and further cumulative studies are needed.