Acute myeloid leukemia (AML) treated with intensive chemotherapy carries a high risk of severe infection. The development of reliable assessment tools to promptly identify patients at risk of developing critical illness is essential to prevent delays in intensive care unit (ICU) admission. This study evaluated the accuracy of quick Sequential Organ Failure Assessment (qSOFA) score, National Early Warning Score (NEWS), and NEWS2 score in predicting ICU admission and sepsis-related mortality in this population. A retrospective analysis was conducted, including 365 episodes of febrile neutropenia in 126 patients. The results showed that all three scores-qSOFA, NEWS, and NEWS2-demonstrated good accuracy for all outcomes, with area under the receiver-operating characteristic curve values for sepsis-related mortality of 0.812, 0.858, and 0.848, respectively. In addition, the scores exhibited excellent accuracy in predicting ICU admission and the composite outcome of ICU admission or sepsis-related mortality. To our knowledge, this is the first study to evaluate the accuracy of NEWS in a population of patients with AML who did not undergo stem cell transplantation. These findings suggest that NEWS and NEWS2 are effective tools for identifying patients with AML at high risk of clinical deterioration during febrile neutropenia, supporting their use in clinical practice.