The Eating Assessment Tool is a self-administered, symptom-specific outcome instrument for dysphagia. The purpose of this study was to assess the validity and reliability of the 10-item Eating Assessment Tool (EAT-10). The investigation consisted of 4 phases: 1) line-item generation, 2) line-item reduction and reliability, 3) normative data generation, and 4) validity analysis. All data were collected prospectively. Internal consistency was assessed with the Cronbach alpha. Test-retest reliability was evaluated with the Pearson product moment correlation coefficient. Normative data were obtained by administering the instrument to a community cohort of healthy volunteers. Validity was assessed by administering the instrument before and after dysphagia treatment and by evaluating survey differences between normal persons and those with known diagnoses. A total of 629 surveys were administered to 482 patients. The internal consistency (Cronbach alpha) of the final instrument was 0.960. The test-retest intra-item correlation coefficients ranged from 0.72 to 0.91. The mean (+/- SD) EAT-10 score of the normal cohort was 0.40 +/- 1.01. The mean EAT-10 score was 23.58 +/- 13.18 for patients with esophageal dysphagia, 23.10 +/- 12.22 for those with oropharyngeal dysphagia, 9.19 +/- 12.60 for those with voice disorders, 22.42 +/- 14.06 for those with head and neck cancer, and 11.71 +/- 9.61 for those with reflux. The patients with oropharyngeal and esophageal dysphagia and a history of head and neck cancer had a significantly higher EAT-10 score than did those with reflux or voice disorders (p <0.001). The mean EAT-10 score of the patients with dysphagia improved from 19.87 +/- 10.5 to 5.2 +/- 7.4 after treatment (p <0.001). The EAT-10 has displayed excellent internal consistency, test-retest reproducibility, and criterion-based validity. The normative data suggest that an EAT-10 score of 3 or higher is abnormal. The instrument may be utilized to document the initial dysphagia severity and monitor the treatment response in persons with a wide array of swallowing disorders.