Objective: To explore the association between the incidence of acute radiation gastritis attributed to postoperative intensity modulated irradiation therapy (IMRT) and the dose volume of intrathoracic stomach of patients with esophageal squamous cell carcinoma (ESCC) after radical esophagectomy. Methods: The authors retrospectively collected the data of 49 ESCC patients who participated in postoperative IMRT treatment after radical esophagectomy, and analyzed the incidence of acute radiation gastritis during the treatment. Results: Among all the 49 patients, acute grade >= 2 radiation gastritis was observed in 19 patients (39%). Receiver operating characteristic (ROC) curve analysis showed that the physical variables, such as stomach D-max, D-mean, length of the whole stomach received 5-40 Gy (LSTT5-LSTT40), and V-10-V-50, were associated with acute radiation gastritis. Patients were grouped according to cutoff values in physical indicators obtained from the ROC curve. Other than V-5, the incidence of acute grade >= 2 radiation gastritis was significantly higher in the group with indicators above cutoff values than that below cutoff values, and the between-group difference was statistically significant in terms of physical indicators. Multivariate analysis suggested that LSTT5 and V-40 could be acted as indicators to predict the incidence of acute grade >= 2 radiation gastritis. Conclusions: In the postoperative IMRT treatment for ESCC patients, protection of intrathoracic stomach is strongly recommended. Dose-volume histogram is a preferable predictive indicator for the occurrence of acute radiation gastritis, especially for the stomach LSTT5 and V-40. Nevertheless, a larger sample size is needed to provide insight into the relevant study.