Background/Aims: The aim of this work was to investigate the efficacy and predictive factors of CLAG treatment in refractory or relapsed (R/R) acute myeloid leukemia (AML) patients. Methods: Sixty-seven R/R AML patients were enrolled in this prospective cohort study and treated by a CLAG regimen: 5 mg/m2/day cladribine (days 1–5), 2 g/m2/day cytarabine (days 1–5), and 300 μg/day filgrastim (days 0–5). The median follow-up duration was 10 months. Results: A total of 57 out of 67 patients were evaluable for remission after CLAG therapy, of whom 57.9% achieved a complete remission (CR) and the overall remission rate was 77.2%. The median overall survival (OS) was 10.0 months, with a 1-year OS of 40.3 ± 6.0% and 3-year OS of 16.7 ± 5.7%. CR at first induction after the initial diagnosis was associated with a favorable CR. Age above 60 years, high risk stratification, second or higher salvage therapy, and bone marrow (BM) blasts ≥42.1% were correlated with an unfavorable CR. Secondary disease, age ≥60 years, high risk stratification, and second or higher salvage therapy were associated with worse OS. Patients developed thrombocytopenia (41, 61%), febrile neutropenia (37, 55%), leukopenia (33, 49%), neutropenia (18, 27%), and anemia (9, 13%). Conclusion: CLAG was effective and well tolerated for R/R AML. BM blasts ≥42.1%, age ≥60 years, high risk stratification, and second or higher salvage therapy were independent factors for a poor prognosis.