Background/Aim: This study aimed to evaluate the association between the change in peripheral eosinophil count during postoperative pelvic radiotherapy and gastrointestinal (GI) toxicities in patients with cervical cancer. Patients and Methods: The medical records of 163 patients with cervical cancer who underwent postoperative concurrent chemoradiotherapy between 2000 and 2016 were analyzed. Results: Among the peripheral blood cell counts, transient elevation of the eosinophil count was observed during radiotherapy. Of the 163 patients, 117 developed grade ≥2 diarrhea during radiotherapy, and 25 patients developed grade ≥2 late GI toxicities. In multivariate analysis, the maximum eosinophil count and age emerged as independent predictors of grade ≥2 acute diarrhea during radiotherapy, while bowel bag V40 Gy and age were predictive of grade ≥2 late GI toxicities. Conclusion: Early detection of transient elevation of eosinophil may facilitate early treatment of acute diarrhea during radiotherapy.