Objective To investigate the efficacy and safety of modified CLAG regimen (cladribine + cytarabine + granulocyte colony-stimulating factor) with reduced chemotherapy dose in the treatment of children with relapsed/refractory acute myeloid leukemia (R/R-AML). Methods The clinical data of children with R/R-AML treated with the modified CLAG regimen from June 2016 to April 2023 were retrospectively analyzed, and the overall response rate (ORR), incidence of adverse reactions, overall survival (OS) rate, and event-free survival (EFS) rate were calculated. Results Among all the children, 17 had recurrent AML, of them 1 had testicular leukemia recurrence, 3 had secondary recurrence in the bone marrow, and the rest had first recurrence in the bone marrow. Nine patients had refractory AML. All children completed 1 course of chemotherapy with modified CLAG regimen, and hematopoietic stem cell transplantation (HSCT) was bridged in 1 patient with no assessed response to treatment, with an ORR of 84.0 % (21/25) in the remaining 25 children. The ORR was 81.3 % (13/16) in the relapsed children and 88.9 % (8/9) in the refractory children. The ORR was 76.9 % (10/13) in children with low risk cytogenetic stratification and 91.7 % (11/12) in children with moderate and high risk cytogenetic stratification. The 64-month OS and EFS rates of all patients were 69.7 % and 63.3 %, respectively. The 64-month OS and EFS rates of 15 children who responded to treatment and successfully bridged allogeneic HSCT were 92.3 %. The most common adverse reactions were myelosuppression (100 %) and gastrointestinal reactions (100 %), followed by infection (57.7 %), elevated transaminases (34.6 %), and bleeding (19.2 %), and one child abandoned treatment due to grade 4 intracranial hemorrhage. All other adverse reactions were improved after symptomatic treatment. Conclusions The modified CLAG regimen with reduced chemotherapy dose is an effective and safe treatment option for children with R/R-AML.