Background Upper endoscopy is not routinely performed to directly detect abnormalities of the duodenal villi. The reliability of the immersion technique for assessment of duodenal villi was evaluated in a series of patients with dyspepsia. Methods A total of 396 patients who were to undergo standard EGD for dyspeptic symptoms were enrolled. Patients with suspected malabsorption were excluded. By performing a “ modified immersion technique,” duodenal villi were scored as the following:definitely present, partially present, or definitely absent. Three duodenal biopsy specimens were obtained from each patient,and villi also were scored histologically as the following: normal,partial villous pattern, or total villous atrophy. Results Sensitivity, specificity, and positive and negative predictive values of the modified immersion technique for detection of total villous atrophy were 100% , 99.7% , 85.7% , and 100% ,respectively. Sensitivity, specificity, and positive and negative predictive values of modified immersion technique for detection of partial villous patterns were 75% , 99.5% , 60% , and 99.7% ,respectively. Sensitivity, specificity, and positive and negative predictive values for modified immersion technique detection of any villous abnormality (partial or total villous atrophy) were 90.9% , 99.5% , 83.3% , and 99.7% , respectively. Conclusions During standard EGD, duodenal evaluation bymodified immersion technique can reliably detect abnormalities of duodenal villi. This simple diagnostic technique may be performed routinely during endoscopic exploration of duodenum. Background Upper endoscopy is not routinely performed to directly detect abnormalities of the duodenal villi. The reliability of the immersion technique for assessment of duodenal villi was evaluated in a series of patients with dyspepsia. Methods A total of 396 patients who were to undergo standard EGD for Patients with suspected malabsorption were excluded. By performing a “modified immersion technique,” duodenal villi were scored as the following: definitely present, partially present, or definitely absent. Three duodenal biopsy specimens were obtained from each patient, and Results Sensitivity, specificity, and positive and negative predictive values ​​of the modified immersion technique for detection of total villous atrophy were 100%, 99.7%, 85.7 %, and 100%, respectively. Sensitivity, specificity, and positive and negative predict ive values ​​of modified immersion technique for detection of partial villous patterns were 75%, 99.5%, 60%, and 99.7%, respectively. Sensitivity, specificity, and positive and negative predictive values ​​for modified immersion technique detection of any villous abnormality (partial or total villous atrophy were 90.9%, 99.5%, 83.3%, and 99.7%, respectively. Conclusions During standard EGD, duodenal evaluation by modificated immersion technique can reliably detect abnormalities of duodenal villi. This simple diagnostic technique may be routinely during endoscopic exploration of duodenum.