The effect of total radiation dose (TRD) on the outcome of patients with postoperative radiotherapy (RT) for squamous cell carcinoma of esophagus was assessed. Sixty-seven patients with esophagectomy, followed by postoperative RT for squamous cell carcinoma of esophagus from June 1984 through February 2001, were retrospectively reviewed. Of these, 13 patients were excluded. No patient had chemotherapy. Patients were classified into two groups based on TRD delivered: TRD of less than 50 Gy (Group A, n = 16) and at least 50 Gy (Group B, n = 38). Follow-up duration of all patients ranged from 4 to 140 months (median, 14). Median TRD of Group A and B were 45 Gy (range, 45-48.6) and 54 Gy (range, 50-59.6), respectively. Median overall survival (OS) and disease-free survival (DFS) of all patients were 15 and 10 months, respectively. Although the TRD of 50 Gy or higher was marginally significant for improved OS (hazard ration [HR] 0.559, P = 0.066), it was statistically significant for improved DFS (HR 0.398, P = 0.011), and locoregional recurrence-free survival (HR 0.165, P = 0.001) with multivariate analysis. Three patients in group A and two in group B experienced a complication of grade 3 or higher. Our study suggests a positive impact of TRD of 50 Gy or higher on DFS and locoregional control, with acceptable morbidity in postoperative RT for patients with squamous cell carcinoma of esophagus. According to the present analysis, TRD should be at least 50 Gy in postoperative RT alone setting.