This study investigated the impact of postoperative radiotherapy (PORT) on dietary function in patients who underwent pharyngoesophageal defect reconstruction using a free jejunal flap. A retrospective chart review of 36 patients who underwent circumferential pharyngoesophageal defect reconstruction using a free jejunal flap was performed. The European Organization for the Research and Treatment of Cancer head and neck cancer module questionnaire was used. Five items related to dietary function were selected and analyzed for changes in scores before and after PORT. Both the PORT and non-PORT groups showed improved dietary function before surgery, and no significant changes were noted at 3 and 12 months postoperatively. Repeated measures ANOVA showed that PORT had no significant impact on dietary function. In univariate analysis, no variable was a significant predictor of the score at 12 months, postoperatively. Previous radiotherapy and neck dissection had a close statistically significant relation. The multivariate analysis showed that neoadjuvant chemotherapy, previous radiotherapy, and neck dissection were significant predictors of the score at 12 months, postoperatively. PORT did not show a significant effect on the 12 months postoperative score. Free jejunal flap is an effective pharyngoesophageal defect reconstruction method that does not cause any dietary function disruption after PORT.