Abstract: Objective To explore the clinical characteristics and prognosis of acute myeloid leukemia (AML) in children with -5/5q-abnormalities. Methods A retrospective analysis was performed for the data of acute myeloid leukemia diagnosed and treated in Department of Pediatrics of Peking University People's Hospital from January 1, 2007 to December 31, 2018, and the clinical manifestations, lab results, treatment and prognosis of children with -5/5q-AML were analyzed. Results Data of 584 children with non-recurrent AML were analyzed in this study. Among them, 12 children(2.05%) were detected with -5/5q-abnormalities, including 4 males, with a median age of 7.5 years and a median follow-up time of 28 months. Three(25%) of the 12 children with -5/5q-AML were transformed from MDS, which was significantly higher than that in children without-5/5q-AML(14/572, 2.4%, P=0.004). There was no significant difference between children with -5/5q-AML and children without -5/5q-AML in terms of gender composition, age at diagnosis, blood routine examination at diagnosis, extramedullary infiltration (hepatomegaly, splenomegaly and lymphnode enlargement), time of symptoms before diagnosis and time of release of myelosuppression after induction chemotherapy. Induction chemotherapy was performed with DAH or ADE regimen in the 12 children with -5/5q-AML. Seven children (58.3%) achieved complete remission; 2 children (16.7%) achieved partial remission; 3 children (25.0%) had no remission. During the follow-up time until July 1, 2019, 1 child lost follow-up; 6 children died ; 5 children survived. The survival time of children with -5/5q-AML (23.3±26.0 months) was significantly shorter than that of children without -5/5q-AML (63.0±10.5 months, P=0.023). The 1-year and 2-year accumulative survival rates of children with -5/5q-AML were 61.9% and 30.9% respectively, which were significantly lower than 81.6% and 77.0% of children without -5/5q-AML, respectively (P＜0.001). Conclusion The detection rate of -5/5q-abnormalities in children with AML was low and the prognosis was poor. The proportion of -5/5q-AML transformed from MDS was high.