OBJECTIVE The aim of this study was to assess whether hematological indices of the peripheral blood are associated with revision surgery in patients with chronic rhinosinusitis (CRS) undergoing endoscopic sinus surgery (ESS). METHODS This retrospective, cross-sectional, single-center study included 541 CRS patients that underwent ESS. Demographics and laboratory parameters were retrieved, and group comparisons were performed. We computed binary logistic regression models to associate clinical characteristics (i.e., aeroallergen allergies, asthma, presence of nasal polyps), absolute blood counts of different leukocyte types (i.e., lymphocytes, neutrophils, basophils, and eosinophils), and hematological indices of the peripheral blood [i.e., neutrophil-to-lymphocyte ratio (NLR), basophil-to-lymphocyte ratio (BLR), eosinophil-to-lymphocyte ratio (ELR), and eosinophil-to-neutrophil ratio (ENR)] with revision surgery as outcome. RESULTS The study population included 435 primary surgeries and 106 revision cases. Patients undergoing revision ESS showed significantly higher absolute preoperative eosinophil counts (381.6 ± 265.6 per µl), ELR (0.205 ± 0.195), and ENR (0.105 ± 0.074) compared to primary cases (all p < 0.001). Binary logistic regression analysis revealed higher odds for revision surgery in patients higher in age (β = 1.026, p < 0.001), with presence of aeroallergen allergies (β = 1.865, p = 0.011), presence of asthma (β = 3.731, p = 0.001), higher preoperative eosinophil counts (β = 1.002, p < 0.001), and higher ELR (β = 155.663, p = 0.015). CONCLUSIONS We found that higher peripheral eosinophil count and higher ELR were associated with revision ESS in CRS patients. Preoperative assessment of hematological indices of the peripheral blood might be a valuable indicator of disease severity, thus facilitating better treatment selection.