Single-dose brachytherapy is a commonly used palliative treatment modality for esophageal carcinoma, however, a considerable number of patients need additional treatment for persistent or recurrent dysphagia. Our aim was to establish predictors of an unfavorable outcome after single-dose brachytherapy.Between December 1999 and July 2002, 95 patients with dysphagia from inoperable esophageal carcinoma were treated with single-dose (12Gy) brachytherapy. Patients were followed-up prospectively by monthly home visits by a specialized research nurse. We investigated the patient and tumor characteristics that influence the risk of persistent dysphagia (continuing dysphagia within 4 weeks after treatment necessitating a second treatment) or recurrent dysphagia (occurring more than 4 weeks after treatment) after single-dose brachytherapy, using logistic and Cox regressions.At 4 weeks after brachytherapy, the dysphagia score was improved in 62/84 (74%) patients. Major complications occurred in 11/95 (12%) patients. In total, 42/95 (44%) patients were treated for persistent (n=18) and/or recurrent dysphagia (n=28). Persistent dysphagia (n=18) was caused by persisting obstructing tumor confirmed at endoscopy, and these patients were treated with stent placement. Patients needing dilation before treatment had a higher risk of persistent dysphagia (odds ratio=4.1; 95% CI 1.3–12). There was a trend toward a higher risk of persistent dysphagia for patients previously treated with chemotherapy (odds ratio=3.2; 95% CI 0.81–12). In total, 34 events of recurrent dysphagia occurred in 28 patients, caused by obstructing tumor regrowth (n=26), food bolus obstruction (n=5), or other reasons (n=3). None of the investigated patient and tumor characteristics had a significant association with the risk of developing recurrent dysphagia. Of all patients needing additional treatment (42/95), those who needed dilation before treatment had a higher risk of persistent and/or recurrent dysphagia (hazard ratio=2.1; 95% CI 1.1–4.1).Patients with stenotic esophageal tumors that cannot be bypassed or who previously underwent chemotherapy are poor candidates for single-dose brachytherapy. For these patients, a higher and/or fractionated dose of brachytherapy or alternative palliative treatment modalities should be considered.