The CFA ratio, calculated using pretreatment C‐reactive protein (CRP), fibrinogen, and albumin levels (CRP × fibrinogen/albumin), was previously reported to be a significant prognostic factor for acute myeloid leukemia (AML). This multicenter retrospective study evaluated the prognostic value of the CFA ratio in 328 adult patients with newly diagnosed AML from April 2000 to March 2018. The median age was 49.5 years (range, 15–75 years), and 60.7% of the population were males. According to the European LeukemiaNet (ELN) risk classification, 67 patients (20.4%) were in the favorable‐risk group, 197 patients (60.1%) in the intermediate‐risk group, and 58 patients (17.7%) in the adverse‐risk group. The median CFA ratio was 1.07 (0–67.69). Based on the calculated cutoff CFA ratio of 1.44, the cohort included 176 and 152 patients with low and high CFA ratios, respectively. At a median follow‐up of 91.2 months, the 7‐year overall survival (OS) and disease‐free survival (DFS) rates were 51.2% and 48.6%, respectively, in the overall cohort. The 7‐year OS rates were 61.7% and 39.0% in the low and high CFA ratio groups, respectively (p < 0.001). The 7‐year DFS rates were 58.1% and 37.0% in the low and high CFA ratio groups, respectively (p = 0.004). In univariate analysis, age ≥50 years, male sex, ELN risk class, and comorbidities were associated with poor OS. Age, ELN risk class, comorbidities, and high CFA ratio were associated with poor OS in multivariate analysis. Subgroup analysis revealed that the CFA ratio was significant in the intermediate and adverse ELN risk classes. These findings indicate the prognostic significance of the CFA ratio in AML.