Abstract: Objective To explore the expression level of retinol-binding protein (RBP) in peripheral blood of patients with acute myeloid leukemia (AML) and its relationships with clinical characteristics of the patients. Methods The expression level of RBP in patients with AML, those with benign hematopathy, and healthy subjects was analyzed. Further, the relationships between age, gender, cytogenetics, French-American-British (FAB) subtypes, molecular mutations, and RBP expression level were analyzed. Results Compared with AML patients, RBP expression level was significantly higher in healthy subjects and those with benign hematopathy. A significantly negative association was observed in patients with M (r=-0.499, P=0.036) and M (r=-0.412, P= 4 5 0.029). Acute promyelocytic leukemia (APL) patients showed higher RBP level compared with those of M (u=-2.085, P=0.037), M 2 4 (u=-3.085, P=0.002), and M (u=-2.249, P=0.024). However, no difference was observed between other FAB subtypes (all P > 0.05). 5 Elderly AML patients had higher RBP level compared with children (t=2.284, P=0.049) and adult patients (t=2.572, P=0.011). Patients carring FLT3-ITD mutation presented with lower RBP level than those without (u=-2.173, P=0.030). Conclusion RBP is not only a nutritional index for AML, but its expression level and relationships with clinical characteristics of AML might offer beneficial information for optimizing AML treatment.