Objective To investigate the correlation between the eosinophil percentage and prognosis in patients with sepsis after intensive care unit(ICU)admission.Methods A retrospec-tive cohort study design was employed,data from adult patients with sepsis or septic shock who were hospitalized for the first time and admitted to the ICU for the first time from the MIMIC-Ⅳ database(version 2.2)were selected.Patients were grouped according to differed eosinophil percentage(＜0.4％and≥0.4％),and the correlation between eosinophil percentage＜0.4％and prognostic out-comes was analyzed.Results A total of 616 patients were included.On the first day after ICU ad-mission,an eosinophil percentage＜0.4％was not significantly associated with prognosis;on the sec-ond day after ICU admission,patients with an eosinophil percentage＜0.4％exhibited a significantly increased 28-day mortality rate(HR=1.572,95％CI,1.119 to 2.208)and in-hospital mortality rate(HR=1.634,95％CI,1.137 to 2.349);on the third day after ICU admission,patients with an eosinophil percentage＜0.4％demonstrated significantly increased 28-day mortality rate(HR=2.072,95％CI,1.482 to 2.896),ICU mortality rate(HR=2.033,95％CI,1.296 to 3.188),and in-hospital mortality rate(HR=2.193,95％CI,1.533 to 3.136).Patients with eosinophil percentages＜0.4％on both the second day and the third day after ICU admission had the worst prog-nosis,with a significantly increased 28-day mortality rate(HR=2.271,95％CI,1.393 to 3.785).Conclusion The eosinophil percentages on the second day and the third day after ICU admission in patients with sepsis are closely correlated with prognosis,particularly aneosinophil percentage＜0.4％on the third day,which is significantly associated with a higher mortality rate.